Blood perfusion system

ABSTRACT

An extracorporeal blood perfusion system includes a disposable assembly and a control unit having a control interface region. The interface region includes pump assemblies for selective pumping of venous blood, arterial blood, cardioplegia solution, suctioned blood and blood removed from the left ventricle. Valve assemblies control the flow of fluids through the assembly and to/from the patient and sensors monitor various fluid parameters including temperature and pressure within the various fluid circuits. The user interface is a functional screen interface for effecting the operation of the control unit and valve assemblies. The screen interface may be a touch screen having objects that corresponds to the component interface region. The display may be selectively controlled to provide graphic depictions of disposable assembly components with corresponding narrative instructions.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.11/333,671, filed Jan. 17, 2006, which is a continuation of U.S.application Ser. No. 09/963,878, filed Sep. 26, 2001, which claims thebenefit under 35 U.S.C. 119(e) of U.S. Provisional Application No.60/235,837, filed on Sep. 27, 2000, the contents of which are herebyincorporated herein by reference in their entirety.

TECHNICAL FIELD

The present invention relates to blood perfusion systems. In oneembodiment, the present invention can be used in cardiopulmonary bypassprocedures.

BACKGROUND

In general, blood perfusion entails forcing blood through the vessels ofa bodily organ. For such purposes, blood perfusion systems typicallyentail the use of one or more pumps in an extracorporeal circuit that isinterconnected with the vascular system of a patient.

Of particular interest, cardiopulmonary bypass surgery requires aperfusion system that provides for the temporary cessation of the heartto create a still operating field by replacing the function of the heartand lungs. Such isolation allows for the surgical correction of vascularstenosis, valvular disorders, and congenital heart defects. In perfusionsystems used for cardiopulmonary bypass surgery, an extracorporeal bloodcircuit is established that includes at least one pump and anoxygenation device to replace the functions of the heart and lungs.

More specifically, in cardiopulmonary bypass procedures oxygen-poorblood, i.e., venous blood, is gravity-drained or suctioned from a largevein entering the heart or other veins in the body (e.g., femoral) andis transferred through a venous line in the extracorporeal circuit. Thevenous blood is pumped to an oxygenator that provides for oxygentransfer to the blood. Oxygen may be introduced into the blood bytransfer across a membrane or, less frequently, by bubbling oxygenthrough the blood. Concurrently, CO₂ is removed across the membrane. Theoxygenated blood is then returned through an arterial line to the aorta,femoral, or other artery.

In addition to the above-noted components, extracorporeal fluid circuitsused for cardiopulmonary bypass procedures also typically provide forthe flow of a cardioplegia mixture through a cardioplegia line into theroot of the aorta, coronaries and/or coronary sinus in order to nourish,arrest, and maintain the arrest of the heart. The cardioplegia mixtureis typically circulated through a heat exchanger prior to patientdelivery. Additional devices that can be employed include a reservoir tohold the venous blood, a heat exchanger to cool or heat the returnedblood, and various filters to keep particles greater than apredetermined size from passage into the patient.

Further, extracorporeal fluid circuits utilized during cardiopulmonarybypass procedures may also include various suction lines. Such lines areemployed to remove blood that collects in the thoracic cavity duringsurgery. Such blood may contain debris such as skin, air, bone chips,etc. and may be salvaged via filtering and routed to a reservoir forsubsequent washing and/or oxygenation and return to the patient. A ventline may also be utilized to remove blood that accumulates in the heartor vasculature (e.g., aortic root, pulmonary artery, etc.) during thebypass procedure. Removal of such accumulated blood may be important toavoid heart distention. The vented blood may be routed to a reservoirfor subsequent oxygenation and return to the patient or washing. Inaddition to the above-noted components, extracorporeal fluid circuitsutilized in connection with cardiopulmonary bypass procedures mayinclude components for the introduction into the blood of variousnutrients and pharmaceuticals.

The various fluid circuitry and components of an extracorporeal circuitare set up by medical personnel prior to the bypass procedure. This canbe a time consuming process since many of the connections are made byhand. As will be appreciated, this set-up procedure is also the sourceof potential error. Any incorrect or leaky connection can jeopardizeboth the success of the surgical procedure and the safety of thepatient. Further, such an approach has entailed the separate setup andmonitoring of each circuit by medical personnel during the course of acardiopulmonary bypass procedure. Further, establishment of theoperative interrelationships between the various circuits has been leftto the attention and coordination of medical personnel. In view of theforegoing it would be desirable to have an integrated perfusion systemwhich is easy to set-up, use and monitor during the bypass procedure.Such a system should eliminate many of the sources of error in theset-up, monitoring and use of conventional extracorporeal perfusioncircuits as well as improve system monitoring and safety. The presentinvention comprises an integrated perfusion system which overcomes manyof the disadvantages of present perfusion systems.

SUMMARY

In view of the foregoing, one objective of the present invention is toprovide a blood perfusion system that provides for simplified set-up andinterconnection/disconnection of various disposable components withmonitoring/control components.

Relatedly, another objective of the present invention is to provide ablood perfusion system that provides for both enhanced/simplifiedmonitoring and control over various operating parameters during amedical procedure, and that concomitantly yields system performanceadvantages.

Yet another objective of the present invention is to provide a bloodperfusion system that readily provides medical personnel withinformation to facilitate setup and/or to facilitate operation,parameter monitoring and alarm response during perfusion procedures.

An additional objective of the present invention is to provide a bloodperfusion system that maintains a wide range of configurability forcustomized use by medical personnel on a patient-specific basis. Whilemultiple embodiments are disclosed, still other embodiments of thepresent invention will become apparent to those skilled in the art fromthe following detailed description, which shows and describesillustrative embodiments of the invention. Accordingly, the drawings anddetailed description are to be regarded as illustrative in nature andnot restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

While the invention is amenable to various modifications and alternativeforms, specific embodiments have been shown by way of example in thedrawings and are described in detail below. The intention, however, isnot to limit the invention to the particular embodiments described. Onthe contrary, the invention is intended to cover all modifications,equivalents, and alternatives falling within the scope of the inventionas defined by the appended claims.

One or more of the above-noted objectives and additional advantages areprovided by the blood perfusion system disclosed herein. The systemintegrates one or more fluid lines and flow-through components in adisposable assembly that operatively interfaces with integrated fluidmonitoring/flow control components of a control unit. Additionalobjectives and advantages may also be realized in the present inventionvia the provision of a multifunctional, graphic user interface that isoperatively interconnected with fluid monitoring/flow controlcomponentry in the disclosed system.

In one aspect, this invention is an extracorporeal blood perfusionsystem for receiving venous blood from a patient and for returningoxygenated blood to the patient in a cardiopulmonary bypass procedure,comprising a disposable assembly including a cartridge and a pluralityof interconnected tubing lines, the cartridge having a plurality ofinternal fluid passageways, wherein a first of the tubing lines isfluidly interconnected with at least one of the plurality of fluidpassageways and wherein the disposable assembly defines a blood circuitfor receiving venous blood from the patient and transferring oxygenatedblood to the patient in a cardiopulmonary bypass procedure; and acontrol unit having a component interface region, the componentinterface region including a cartridge interface region for operativelyinterfacing with the cartridge, and a first pump for operativelyinterfacing with a the blood circuit, wherein the venous blood is pumpedthrough the blood circuit by the first pump.

The disposable assembly may further comprise a reservoir foraccumulating the venous blood from the patient, and the componentinterface region may further comprise a flow control clamp forcontrolling the flow of venous blood through a second tubing line to thereservoir. The flow control clamp may be controllable to maintain atleast one of a predetermined relative flow percentage through the secondtubing line to the reservoir and a predetermined fluid volume within thereservoir. The disposable assembly may further comprise an oxygenatorconnected in the blood circuit downstream from the reservoir, and thefirst pump may be configured to pump accumulated venous blood from thereservoir through the oxygenator to provide for the transfer of theoxygenated blood to the patient. The disposable assembly of theperfusion system may also include a reservoir for accumulating thevenous blood from the patient, and the component interface region mayfurther comprises a sensor for detecting the presence of gaseous bubbleswithin the oxygenated blood and at least one valve assembly configuredfor diverting the flow of the oxygenated blood to the reservoir upondetection of gaseous bubbles in the oxygenated blood by the sensor.

The disposable assembly further defines a cardioplegia circuit forsupplying a cardioplegia solution to the patient, the cardioplegiacircuit including a fluid interconnection with the blood circuit forflowing at least a portion of the oxygenated blood to one of theplurality of fluid passageways for mixture with a cardioplegia solution.The component interface region may include a plurality of sensorspositioned for monitoring an oxygen saturation, hematocrit andtemperature of the venous blood received in the blood circuit and mayinclude a pressure sensor positioned for monitoring a fluid pressure ofthe oxygenated blood in the blood circuit. The control unit of thesystem is operable to automatically suspend operation of the first pumpwhen the pressure sensor detects a fluid pressure greater or less than apredetermined level and the cartridge comprises a housing including afirst rigid portion connected to a second flexible portion. Thecartridge interface region may further include a pressure sensorconfigured to sense fluid pressure in an internal passageway of thecartridge through the second flexible portion of the housing. Thecartridge interface region optionally includes a valve actuator and thecartridge optionally includes a valve station, the valve station beingin fluid communication with at least two of the internal passageways,the valve station having a flexible member configured to be moveablefrom a first position allowing fluid flow between the at least twointernal passageways and a second position preventing fluid flow betweenthe at least two internal passageways, the valve actuator beingconfigured to interface with the flexible member to cause movement ofthe flexible member between the first and second positions.

In a second aspect, this invention is an extracorporeal blood perfusionsystem for use in receiving venous blood from a patient and forreturning oxygenated blood to the patient, comprising a disposableassembly including a cartridge and a plurality of interconnected tubinglines, the disposable assembly defining a blood circuit for receivingvenous blood from the patient and transferring oxygenated blood to thepatient and a cardioplegia circuit for transferring a cardioplegiasolution to the patient; a control unit having a component interfaceregion including a cartridge interface region for operativelyinterfacing with the cartridge; and a first pump for controlling theflow of venous blood through a first tubing loop comprising the bloodcircuit, and a second pump for controlling the flow of cardioplegiasolution through a second tubing loop comprising the cardioplegiacircuit, wherein the second tubing loop is fluidly interconnected ateach end thereof to the cartridge.

Preferably, the first and second pumps are substantially verticallyaligned in relative fixed relation, and wherein the first pump islocated below the second pump. The component interface region mayfurther include a third pump for controlling the flow of blood through athird tubing loop comprising the cardioplegia circuit, wherein the thirdtubing loop is fluidly interconnected at each end thereof to thecartridge, and wherein the second pump and the third pump combinativelycontrol the flow of cardioplegia solution to the patient. The second andthird pumps may be substantially vertically aligned in relative fixedrelation. The system's disposable assembly further defines a bloodrecovery circuit for receiving vented blood from a left ventricle of thepatient and the component interface region further comprises a fourthpump for controlling the flow of the vented blood through a fourthtubing loop comprising the blood recovery circuit. The first, second,third and fourth pumps may be in substantial vertical alignment inrelative fixed relation.

The disposable assembly further defines a first autologous blood circuitfor receiving autologous blood from the patient, and the componentinterface region further comprises a fifth pump for controlling the flowof the autologous blood through a fifth tubing loop comprising the firstblood recovery circuit, the fifth pump being positioned to create duringoperation a suction at a free end of the first blood recovery circuit.The first, second, third, fourth and fifth pumps preferably are insubstantial vertical alignment in relative fixed relation.

In a third aspect, this invention is an extracorporeal blood perfusionsystem for use in receiving venous blood from a patient's heart and fortransferring oxygenated blood back to the patient, comprising adisposable assembly including a reservoir, an oxygenator and a pluralityof tubing lines, wherein a first tubing line is connected fortransferring venous blood from the patient to the reservoir, and asecond tubing line is connected for transferring oxygenated blood to thepatient; and a control unit having a component interface panel includinga clamp assembly for controlling the rate of transfer of the venousblood through the first tubing line to the reservoir.

The component interface panel may further include a first pump connectedfor pumping the venous blood from the reservoir through the oxygenatorand for pumping the oxygenated blood through the second tubing line tothe patient. The clamp assembly may include a plunger and a lidconfigured for clamping the first tubing line therebetween. The controlunit is configured to selectively control advancement and retraction ofthe plunger relative to the lid, wherein a predetermined degree ofocclusion of the first tubing line by the clamp assembly is selectableby a user.

In a fourth aspect, this invention is an extracorporeal blood perfusionsystem for use in receiving venous blood from a patient and returningoxygenated blood to the patient, comprising a disposable assemblyincluding a cartridge and a plurality of tubing lines, the disposableassembly defining at least a blood circuit for receiving venous bloodfrom the patient and returning oxygenated blood to the patient and acardioplegia circuit for transferring a cardioplegia solution to thepatient; and a control unit having a component interface panelcomprising a cartridge interface region operatively interfacing with thecartridge, and including a first pressure sensor for monitoring a fluidpressure within the blood circuit, and a second pressure sensor formonitoring a fluid pressure within the cardioplegia circuit; and firstand second pumps, the first pump being configured to control a flow rateof the oxygenated blood in the blood circuit, and the second pump beingconfigured to at least partially control a flow rate of the cardioplegiasolution in the cardioplegia circuit.

The disposable assembly further defines at least a first blood recoverycircuit for receiving vented blood from a left ventricle of the patient,and the cartridge interface region comprises a third pressure sensorconfigured for monitoring a fluid pressure within the blood recoverycircuit. The disposable assembly also further defines at least a firstautologous blood circuit configured for suctioning autologous blood fromthe patient, and the cartridge interface region comprises a fourthpressure sensor configured for monitoring a fluid pressure within thefirst autologous blood circuit.

In a fifth aspect, this invention is an extracorporeal blood perfusionsystem for use in receiving blood from a patient's heart and fortransferring the blood back to the patient comprising a disposableassembly including a cartridge and a plurality of tubing lines, thedisposable assembly defining a blood circuit for receiving blood fromthe patient and for transferring the blood back to the patient, thecartridge including a plurality of internal passageways and at least onereservoir containing a cardioplegia solution, the at least one reservoirbeing configured to be interconnectable to the cartridge to flow thecardioplegia solution into at least one of the plurality of fluidpassageways of the cartridge; and a control unit having a cartridgeinterface region for operatively interfacing with the cartridge, thecartridge interface region having at least one sensor configured forsensing one of a pressure and temperature of a fluid flowing through theat least one fluid passageway of the cartridge. The at least one sensormay comprise a first sensor for sensing fluid pressure and a secondsensor for sensing fluid temperature within the at least one fluidpassageway of the cartridge. The cartridge may further comprise a filterconfigured for filtering the cardioplegia solution. The cartridge mayalso comprise a trap configured to remove gaseous bubbles from the fluidflowing through the at least one fluid passageway of the cartridge. Thedisposable assembly may include a cardioplegia tubing line fluidlyinterconnected to the at least one internal passageway of the cartridgefor transferring the cardioplegia solution to the patient.

In a sixth aspect, this invention is an extracorporeal blood perfusionsystem for use in receiving venous blood from a patient and returningoxygenated blood to the patient, comprising a disposable assemblyincluding a plurality of fluid channels, the disposable assemblydefining a blood circuit for receiving venous blood from the patient andreturning oxygenated blood to the patient, the plurality of fluidchannels including a first fluid channel fluidly interconnected to theblood circuit, the first fluid channel being at least partially definedby a first tubing line, and a second fluid channel being at leastpartially defined by a second tubing line, the first and second fluidchannels being fluidly interconnected to a third fluid channel; and acontrol unit including a component interface region comprising a firstpump connected for operatively interfacing with the first tubing line,wherein oxygenated blood is pumped through the first tubing line by thefirst pump, and a second pump connected for operatively interfacing withthe second tubing line, the second pump being configured to pump acardioplegia solution through the second tubing line, the control unitbeing configured such that a volumetric ratio of the cardioplegiasolution and the oxygenated blood is selectively established in thethird fluid channel by control of the first and second pumps.

The disposable assembly comprises a cartridge having a first internalpassageway interconnected with the first tubing line, a second internalpassageway interconnected with the second tubing line, and a thirdinternal passageway at least partial defining the third fluid channel,wherein the first, second and third internal passageways adjoin withinthe cartridge. The cartridge may further comprise a bubble trapconfigured for removing gaseous bubbles from fluid passing through thethird internal passageway. The component interface region may comprise acartridge interface region for operatively interfacing with thecartridge, the cartridge interface region including a pressure sensorconfigured for monitoring a fluid pressure within the third internalpassageway.

In a seventh aspect, this invention is an extracorporeal blood perfusionsystem for receiving venous blood from a patient and transferringoxygenated blood to the patient, comprising a disposable assemblyincluding a cartridge and a plurality of tubing lines, the disposableassembly defining a blood circuit for receiving venous blood from thepatient and transferring oxygenated blood to the patient, and a bloodrecovery circuit for receiving at least one of autologous blood from thepatient and vented blood from a left ventricle of the patient; and acontrol unit having a component interface region configured forcontrolling the flow of fluids in each of the blood and blood recoverycircuits.

The cartridge includes a sequestration reservoir configured foraccumulating the at least one of autologous blood and vented blood. Theblood circuit includes a venous reservoir connected for accumulating thevenous blood, and the component interface region includes a valvepositioned for selectively controlling the flow of fluid from thesequestration reservoir to the venous reservoir. The blood recoverycircuit may be connected to receive the vented or suctioned blood, andthe component interface region may include a valve assembly, the controlunit being configured to selectively operate the valve assembly in amanner that controls the flow of the vented blood directly from theblood recovery circuit into the blood circuit.

In an eighth aspect, this invention is an extracorporeal blood perfusionsystem for use in receiving venous blood from a patient and transferringoxygenated blood to the patient, comprising a disposable assemblydefining a plurality of fluid circuits, including a blood circuit forreceiving venous blood from the patient and transferring oxygenatedblood to the patient; a control unit having a component interface regionfor operatively interfacing with the disposable assembly, the componentinterface region including a flow controller to control the rate of flowof fluids through a first of the plurality of fluid circuits; and a userinterface, operatively interconnected with the flow controller,including a display configured to be selectively controllable to displayan object that provides a functional interface for user control over theoperation of the flow controller.

The plurality of fluid circuits further includes a cardioplegia circuitfor supplying a cardioplegia solution to the patient, and wherein thedisplay is configured to be selectively controllable to display graphicdepictions of each of the blood and cardioplegia circuits. The flowcontroller may comprise a first valve operatively interfacing with theblood circuit, and a second valve operatively interfacing with thecardioplegia circuit. The graphic depiction of the blood circuitcomprises a first object corresponding with the first valve, the displaybeing configured such that the first object provides a functionalinterface for user control over the operation of the first valve, andthe graphic depiction of the cardioplegia circuit comprises a secondobject corresponding with the second valve, the display being configuredsuch that the second object provides a functional interface for usercontrol over the second valve. The display may be configured such thatthe first object provides a visual indication of whether the first valveis open or closed, and the second object provides a visual indication ofwhether the second valve is open or closed. The functional interfacecorresponding with the first object and the functional interfacecorresponding with the second object preferably are defined by atouch-screen attribute of the display. The flow controller may comprisea first pump configured to operatively interface with the blood circuit,and a second pump configured to operatively interface with thecardioplegia circuit. The display may be configured such that thegraphic depiction of the blood circuit comprises a first flow rateindicator corresponding with the first pump to indicate a current fluidflow rate established by the first pump, and the graphic depiction ofthe cardioplegia circuit comprises a second flow rate indicatorcorresponding with the second pump to indicate a current fluid flow rateestablished by the second pump. The component interface region may alsoinclude at least a first sensor configured to operatively interface withone of the plurality of fluid circuits to monitor a first fluidparameter corresponding with fluid flowing through the one fluidcircuit, and the user interface may be operatively interconnected withthe first sensor to display a value corresponding with the monitoredfirst fluid parameter and to provide a user alert when the monitoredfirst fluid parameter is outside of a predetermined range. The displayis configured to be selectively controllable to display an objectselectable by a user for setting the predetermined range.

In a ninth aspect, this invention is an extracorporeal blood perfusionsystem for use in receiving venous blood from a patient and transferringoxygenated blood to the patient, comprising a disposable assemblydefining a plurality of fluid circuits, including a blood circuit forreceiving venous blood from the patient and transferring oxygenatedblood to the patient; a control unit including a component interfaceregion for operatively interfacing with the disposable assembly, thecomponent interface region including at least one sensor configured tooperatively interface with one of the plurality of fluid circuits tomonitor a first fluid parameter corresponding with a fluid flowingthrough the one fluid circuit; and a user interface operativelyinterconnected with the component interface region and configured todisplay a value corresponding with the monitored first parameter and toprovide a user alert when the monitored first parameter is outside of apredetermined range.

The user interface is configured to be selectively controllable by auser to display an object corresponding with the at least one sensor,the interface being configured such that the object provides afunctional interface for setting the predetermined range by a user. Thefunctional interface may be provided by the object via a touch-screenattribute of the user interface. The user interface may further comprisea control knob configured such that upon functional interface by a userwith the object, the control knob may be manipulated by a user to setthe predetermined range, and the user interface may be configured to beselectively controllable by a user to display a graphic depictioncorresponding with the blood circuit, the graphic depiction including aplurality of objects corresponding with a plurality of sensorscomprising the component interface region to monitor a correspondingplurality of fluid parameters corresponding with fluid flowing throughthe blood circuit. The user interface also may be configured such thatthe plurality of monitored fluid parameters includes oxygen saturation,hematocrit and temperature of the venous blood. The component interfaceregion may further comprise a flow controller to control the flow offluid through the one fluid circuit, and the control unit comprises aprocessor, operatively interconnected with the flow controller and thefirst sensor, wherein the processor is operable to automatically providea control signal to the flow controller when the monitored firstparameter is outside of the predetermined range.

In a tenth aspect, this invention is an extra corporeal blood perfusionsystem, comprising a disposable assembly defining a plurality of fluidcircuits; a control unit having a component interface region foroperatively interfacing with the disposable assembly, the componentinterface region being configured to monitor a plurality of fluidparameters corresponding with fluid flowing through the plurality offluid circuits; and a user interface, operatively interconnected withthe component interface region, including a display having at least twodisplay regions selected from a group of (1) a first display region forcontinuously displaying at least a first set of values correspondingwith each of a first set of the plurality of monitored parameters; (2) asecond display region for selectively displaying one of a plurality ofgraphic depictions, each graphic depiction corresponding with a givenone of the plurality of fluid circuits; and (3) a third display regionfor displaying user alert indications when a given one of the pluralityof monitored parameters is outside of a corresponding predeterminedrange. The disposable assembly defines a blood circuit configured toreceive venous blood from a patient and to return oxygenated blood tothe patient, and the first set of values may comprise an oxygensaturation value, blood hematocrit value and temperature value for thevenous blood. The first display region may be configured to continuouslydisplay a second set of values corresponding with each of a second setof the plurality of monitored parameters, and the second set of valuesmay comprise a pressure value, a flow rate value and a temperature valuefor the oxygenated blood. The disposable assembly defines a cardioplegiacircuit for supplying a cardioplegia solution to a patient, and thefirst set of values may comprise a fluid pressure value, a flow ratevalue and a temperature value of the cardioplegia solution. Thedisposable assembly also defines a blood circuit for receiving venousblood from a patient and transferring oxygenated blood to the patient,and a cardioplegia circuit for supplying a cardioplegia solution to thepatient; the first display region may be configured to continuouslydisplay a second set of values corresponding with each of a second setof the plurality of monitored parameters, and the first set of valuesmay comprise a fluid pressure value, flow rate value and temperaturevalue of the cardioplegia solution, and the second set of values maycomprise at least one of a first subset of values comprising an oxygensaturation value, blood hematocrit value and temperature value for thevenous blood, and a second subset of values comprising a fluid pressurevalue, flow rate value and temperature value for the oxygenated blood.

The first display region preferably is configured to continuouslydisplay at least a second set of values corresponding with each of asecond set of the plurality of monitored parameters, wherein the secondset of values comprises at least one of a bolus volume valuecorresponding with an amount of the cardioplegia solution to be suppliedto the patient and an ischemic time value corresponding with an elapsedamount of time between successive periods during which the cardioplegiasolution is supplied to a patient. The disposable assembly defines ablood circuit for receiving venous blood from a patient and transferringoxygenated blood to the patient and includes a blood reservoir, and thefirst display region may be configured to continuously display a graphicrepresentation of the volumetric fluid content of the reservoir on areal-time basis. The first display region may further comprise a numericdisplay of the volumetric amount of fluid contained by the reservoir ona real-time monitored basis. The disposable assembly may comprise ablood circuit for receiving venous blood from a patient and transferringoxygenated blood to a patient, wherein the blood circuit includes avenous reservoir for receiving the venous blood; the component interfaceregion may comprise a clamp configured to control the rate of flow ofthe venous blood to the reservoir; and the first display region mayinclude an object providing a functional interface for a user toestablish a degree to which the clamp is open for passage of the venousblood to the reservoir. Preferably, the user interface further comprisesa control knob, the user interface being configured such that uponfunctional interface with the object by a user, the control knob ismanipulatable by a user to establish the degree to which the clamp isopen.

In an eleventh aspect, this invention is an extracorporeal bloodperfusion system, comprising a disposable assembly including a cartridgeand a plurality of tubing lines, the disposable assembly defining ablood circuit for receiving venous blood from a patient and transferringoxygenated blood to the patient, and a cardioplegia circuit fortransferring a cardioplegia solution to the patient; a control unitincluding a component interface region for operatively interfacing withthe disposable assembly; and a user interface, operably interconnectedwith the component interface region, including a display, the displaybeing configured for displaying narrative instructions and correspondinggraphic depictions for loading the disposable assembly on the componentinterface region. The display preferably is configured such that thenarrative instructions and corresponding graphic depictions arepresented in a plurality of sequentially presented display boxes.

In a twelfth aspect, this invention is an extracorporeal blood perfusionsystem, comprising a disposable assembly defining a plurality of fluidcircuits; a control unit having a component interface region including aflow controller configured to control the flow of fluids through atleast a first of the plurality of fluid circuits, and at least a firstsensor for monitoring a first fluid parameter corresponding with fluidflowing through the first fluid circuit, wherein the flow controller isconfigured to be controllable to automatically adjust the flow of fluidthrough the first fluid circuit when the first sensor detects that thefirst parameter is outside of a predetermined range; and a userinterface, operatively interconnected with the component interfaceregion, including a display configured for selectively displayingfunctional objects, at least one of the objects being employable by auser to set the predetermined range.

The disposable assembly defines a blood circuit for transferring venousblood from a patient and returning oxygenated blood to the patient, theflow controller comprises a first pump for controlling the flow rate ofthe oxygenated blood, and the first sensor is configured to monitor afluid pressure of the oxygenated blood, wherein the first pump iscontrollable to automatically stop when the first sensor detects thatthe fluid pressure is outside of a predetermined pressure range. Thedisposable assembly optionally may define a blood circuit for receivingvenous blood from a patient and returning oxygenated blood to thepatient, the blood circuit including a reservoir for accumulating thevenous blood and an oxygenator, wherein the flow controller comprises afirst pump for controlling a flow rate of the venous blood from thereservoir through the oxygenator to provide the oxygenated blood, andwherein the first sensor monitors a volumetric content of the reservoir,wherein the first pump is configured to be controllable to automaticallystop the flow of the oxygenated blood when the first sensor detects thatthe volumetric fluid content of the reservoir is outside of apredetermined range. The disposable assembly may also define acardioplegia circuit for supplying a cardioplegia solution to a patient,the flow controller may comprise at least a first pump connected forcontrolling a flow rate of the cardioplegia solution, and the firstsensor may monitor a fluid pressure of the cardioplegia solution, thefirst pump being configured to be controllable to automatically stop theflow of the cardioplegia solution when the first sensor detects a fluidpressure outside of a predetermined pressure range.

The disposable assembly may also define a blood circuit for receivingvenous blood from a patient and returning oxygenated blood to thepatient, the blood circuit including a reservoir for accumulating thevenous blood and providing the accumulated venous blood for oxygenation,and the flow controller may include a flow control clamp configured forcontrolling the flow of venous blood to the reservoir and a first pumpconfigured for controlling the flow rate of the oxygenated blood, andthe first sensor may be configured to monitor a fluid level within thereservoir, such that one of the flow control clamp and the first pump isautomatically controllable to maintain a predetermined fluid level inthe reservoir based upon an output provided by the first sensor.

In a thirteenth aspect, this invention is extracorporeal blood perfusionsystem, comprising a disposable assembly defining a plurality of fluidcircuits; a control unit including a component interface region foroperatively interfacing with the disposable assembly; a user interface,operatively interconnected with the component interface region,including a display configured to provide a context-driven displayregion, the context-driven display region displaying a plurality of tabsprovided for functional interface with a user, and any one of aplurality of information sets, each information set corresponding with agiven one of the tabs, wherein separate first and second tabs areprovided in corresponding relation to at least a first fluid circuit anda second fluid circuit comprising the plurality of fluid circuits.

The first circuit may be a blood circuit for receiving venous blood froma patient and returning oxygenated blood to the patient, and the secondfluid circuit may be a cardioplegia circuit for supplying cardioplegiato the patient, such that the information sets corresponding with thefirst and second tabs comprise graphic depictions of the blood circuitand the cardioplegia circuit, respectively. The component interfaceregion may comprise a first sensor for monitoring a parameter of fluidflowing in the blood circuit and a first pump for controlling the flowrate of the oxygenated blood in the blood circuit, and a second sensorfor monitoring a parameter of the cardioplegia solution flowing in thecardioplegia circuit and a second pump for controlling the flow rate ofthe cardioplegia solution.

In a fourteenth aspect, this invention is an extracorporeal bloodperfusion system for receiving venous blood from a patient and forreturning oxygenated blood to the patient in a cardiopulmonary bypassprocedure comprising a cardiopulmonary circuit configured to receivevenous blood from the patient and to return oxygenated blood to thepatient; a cardioplegia circuit configured for delivering a cardioplegiasolution to the patient; a cardiotomy circuit configured for withdrawingfluids from the patient; and a cartridge having a housing defining aplurality of internal passageways connected to the cardiopulmonarycircuit, the cardioplegia circuit, and the cardiotomy circuit.

The system further comprises a ventricular vent circuit configured fordraining blood from the patient's left ventricle and wherein the housingof the cartridge defines a plurality of internal passageways connectedto the cardiopulmonary circuit, the cardioplegia circuit, the cardiotomycircuit, and the ventricular vent circuit. The housing of the cartridgemay comprise a first rigid portion connected to a second flexibleportion in a manner defining at least in part the plurality of internalpassageways. The first rigid portion may comprise a translucent materialconfigured to allow viewing of fluid in an internal passageway and/or abubble detector connected for detecting bubbles in the cardiopulmonarycircuit. The bubble detector is positioned for detecting bubbles in atleast one of the internal passageways. The system may include a filterpositioned for filtering at least one of blood, cardioplegia solution,and fluid flowing in an internal passageway. The first portion of thecartridge may define a plurality of inlet and exit ports in fluidcommunication with the plurality of internal passageways.

In a fifteenth aspect, this invention is an extracorporeal bloodperfusion system comprising a disposable assembly comprising a pluralityof components interconnected by a plurality of tubing lines, theplurality of components including a cartridge and at least one of anoxygenator, a heat exchanger, a blood reservoir and an arterial filter,the cartridge having a housing defining a plurality of internal fluidpassageways, the tubing lines interconnecting the components to define ablood circuit for receiving venous blood from a patient and returningoxygenated blood to the patient; and a control unit having an interfaceregion for operatively interfacing with the disposable assembly, theinterface region including a plurality of sensors for sensing at leastone fluid characteristic including pressure, temperature, level and airbubbles, and for generating a signal indicative of each fluidcharacteristic sensed, at least one of the sensors being positioned tosense a characteristic of fluid in an internal passageway of thecartridge, the control unit further including at least one flow controlelement configured to control the rate of flow of blood in the bloodcircuit in response to at least one of the sensed fluid characteristics.

The flow control element may be a roller pump attached to a tubing linein the blood circuit.

In a sixteenth aspect, this invention is a for maintaining the level ofblood in a venous reservoir at a predetermined level when the reservoiris used in an extracorporeal blood perfusion system which includes acardiopulmonary blood circuit for receiving venous blood from a patientthrough a venous line, oxygenating the blood in an oxygenator, andreturning the oxygenated blood to the patient through an arterial line,the venous reservoir having an inlet connected to the venous line and anoutlet connected to the oxygenator, the method comprising providing alevel control element operatively connected to the venous reservoir forcontrolling at least one of the rate of flow of venous blood out of thevenous reservoir and the rate of flow of venous blood into the venousreservoir through the venous line; providing a level sensor configuredto continuously monitor the level of blood in the venous reservoir andto provide level signals indicative of the blood level; and providing acontrol unit connected to received the level signals, the control unitbeing connected to the level control element and being configured tofunctionally control operation of the level control element such thatwhen the level signals are indicative of a level below the predeterminedlevel the flow control element is caused to increase venous blood levelin the venous reservoir by at least one of increasing venous blood flowinto the venous reservoir and decreasing venous blood flow out of thevenous reservoir, and when the level signals are indicative of a levelwhich is above the predetermined level the flow control element iscaused to decrease venous blood level in the venous reservoir by atleast one of decreasing venous blood flow into the venous reservoir andincreasing venous blood flow out of the venous reservoir.

The step of providing a level control element may comprise providing apump connected to the outlet of the venous reservoir and the step ofproviding a control unit may comprise providing a control unit which isconfigured such that when the level signals are indicative of a levelbelow the predetermined level the pump is caused to slow the flow ofblood out of the venous reservoir and when the level signals areindicative of a level above the predetermined level the pump is causedto increase the flow of blood out of the venous reservoir. The step ofproviding a level control element may comprise providing a flow controlmember operatively connected to the venous line for controlling the rateof blood flow through the venous line into the venous reservoir and thestep of providing a control unit may comprise providing a control unitwhich is configured such that when the level signals are indicative of alevel below the predetermined level the flow control member is caused toincrease the flow of blood into the venous reservoir and when the levelsignals are indicative of a level above the predetermined level the flowcontrol member is caused to decrease the flow of venous blood into thereservoir. The step of providing a level control element comprisesproviding a venous line clamp attached to the venous line. The venousreservoir may be a sealed reservoir, and the step of providing a levelcontrol element may comprise connecting a vacuum source to the venousreservoir and the step of providing a control unit may compriseproviding a control unit which is configured such that when the levelsignals are indicative of a level below the predetermined level theamount of vacuum applied to the venous reservoir is increased and whenthe level signals are indicative of a level which is above thepredetermined level the amount of vacuum applied to the venous reservoiris decreased.

In a seventeenth aspect, in an extracorporeal blood perfusion system forreceiving blood from a patient through a venous line, oxygenating theblood, and returning the oxygenated blood to the patient through anarterial line, a method of preventing the return of oxygenated bloodcontaining gaseous bubbles to the patient, the extracorporeal bloodperfusion system including a cardiopulmonary blood circuit having aplurality of tubing lines interconnecting a venous reservoir, a bloodoxygenator and an arterial blood filter, this invention is a methodcomprising connecting the blood perfusion system for receiving venousblood from the patient and returning oxygenated blood to the patient;providing an air purge line including a purge valve having an openposition for opening the purge line and a closed position for closingthe purge line; fluidly connecting a first end of the purge line with anoutlet of the oxygenator and a second end of the purge line with aninlet of the venous reservoir; and providing a control unit having asensor for determining the presence of gaseous bubbles in a tubing lineconnected to an outlet of the oxygenator, the control unit beingconnected to the first pump for controlling the speed of the first pumpand being connected to the purge valve for automatically opening thepurge valve when gaseous bubbles are sensed by the sensor such that atleast a portion of the oxygenated blood is diverted from the patientthrough the air purge line back to the venous reservoir.

The step of fluidly connecting the first and second ends of the purgeline may include connecting the first end of the purge line to a purgeport on the arterial blood filter. The method also may include providingan arterial valve in the arterial line, the arterial valve having anopen position for opening the arterial line and a closed position forclosing the arterial line and the step of providing a control unit mayinclude providing a control unit connected to the arterial valve forautomatically closing the arterial valve when gaseous bubbles are sensedby the sensor. The step of providing a control unit may includeproviding a control unit connected to the first pump for automaticallyslowing the speed of the first pump when gaseous bubbles are sensed bythe sensor.

In an eighteenth aspect, this invention is a method of automaticallypriming an extracorporeal blood perfusion system which includes acardiopulmonary blood circuit for receiving venous blood from a patient,oxygenating the blood and returning the oxygenated blood to the patient,the blood circuit being defined by a plurality of tubing linesinterconnecting a plurality of components including a venous reservoirand an oxygenator, the blood perfusion system further including a firstpump for causing fluid to flow in the blood circuit, the methodcomprising providing a source of priming fluid; providing a primingfluid valve; connecting the source of priming fluid to the blood circuitthrough the priming fluid valve in a manner such that the flow ofpriming fluid to the blood circuit is controllable by the priming fluidvalve; providing a control unit having a component interface region forfunctionally interfacing with and controlling the first pump and thepriming fluid valve, the control unit having a plurality of selectableoperational modes including an automatic priming mode whereby uponselection of the automatic priming mode the control unit opens thepriming fluid valve and controls the speed of the first pump to primethe blood circuit; and selecting the automatic priming mode on thecontrol unit to prime the blood circuit including the venous reservoir,oxygenator and interconnecting tubing.

The plurality of components may include a heat exchanger and an arterialblood filter and wherein the step of selecting the automatic primingmode comprises priming of the blood circuit including the venousreservoir, oxygenator, heat exchanger, arterial blood filter andinterconnecting tubing. The blood perfusion system may include acardioplegia circuit for providing a cardioplegia solution to thepatient, the cardioplegia circuit including a second pump for causingfluid to flow in the cardioplegia circuit and wherein the step ofproviding a control unit includes providing a control unit having acomponent interface region for functionally interfacing with andcontrolling the first and second pumps and the priming fluid valve, thecontrol unit having a plurality of selectable operational modesincluding an automatic priming mode whereby the control unit opens thepriming fluid valve and controls the speed of the first and second pumpsto prime the blood circuit and the cardioplegia circuit, and wherein thestep of selecting the automatic priming mode causes the blood circuitand the cardioplegia circuit to be automatically primed.

In a nineteenth aspect, in an extracorporeal blood perfusion system forreceiving venous blood from a patient through an end of a venous line,oxygenating the blood and returning the oxygenated blood to the patientthrough an end of an arterial line, the perfusion system including acardiopulmonary blood circuit defined by a plurality of tubing linesinterconnecting a plurality of components including a venous reservoirand oxygenator, the perfusion system also including a first roller pumpattached to a tubing line of the cardiopulmonary blood circuit, thisinvention is a method of testing for leaks and pump loading andocclusion in the cardiopulmonary blood circuit comprising sealing theends of the venous and arterial lines; providing a control unit having apressure sensor for measuring pressure in the cardiopulmonary bloodcircuit, the control unit being connected for controlling the operationof the first roller pump, the control unit having a cardiopulmonaryblood circuit test mode, selection of which causes the control unit toautomatically operate the first roller pump until a first predeterminedpressure is measured by the sensor, and to monitor the pressure over apredetermined period of time to determine whether the decay of pressureis within a predetermined acceptable range; and selecting thecardiopulmonary blood circuit test mode of the control unit.

In a twentieth aspect, in an extracorporeal blood perfusion system forreceiving venous blood from a patient through an end of a venous line,oxygenating the blood and returning the oxygenated blood to the patientthrough an end of an arterial line, the perfusion system including acardiopulmonary blood circuit defined by a plurality of tubing linesinterconnecting a plurality of components including a venous reservoirand oxygenator, a cardioplegia circuit for delivering a cardioplegiasolution to the patient through an end of a cardioplegia line, and asuction circuit for removing blood and other fluids from the patientthrough an end of a suction line, a method of testing for leaks and forproper pump loading and occlusion in the cardiopulmonary blood circuit,the cardioplegia circuit, and the suction circuit, this invention is amethod comprising sealing the ends of the venous, arterial, cardioplegiaand suction lines; providing a control unit having at least one pressuresensor for measuring fluid pressure in the cardiopulmonary bloodcircuit, the cardioplegia circuit and the suction circuit, the controlunit being connected for controlling the operation of the first, secondand third roller pumps, the control unit having a cardiopulmonary bloodcircuit test mode, selection of which causes the control unit toautomatically operate the first roller pump until a first predeterminedpressure is measured by the sensor and to monitor the pressure over afirst predetermined period of time to determine whether the decay ofpressure is within a first predetermined acceptable range, the controlunit further having a cardioplegia circuit test mode, selection of whichcauses the control unit to automatically operate the second roller pumpuntil a second predetermined pressure is measured by the sensor and tomonitor the pressure over a second predetermined period of time todetermine whether the decay of pressure is within a second predeterminedacceptable range, the control unit further having a suction circuit testmode, selection of which causes the control unit to automaticallyoperate the third roller pump until a third predetermined pressure ismeasured by the sensor and to monitor the pressure over a thirdpredetermined period of time to determine whether the decay of pressureis within a third predetermined acceptable range; selecting thecardiopulmonary blood circuit test mode of the control unit to test forleaks in the cardiopulmonary blood circuit and proper pump loading andocclusion of the first pump; selecting the cardioplegia circuit testmode of the control unit to test for leaks in the cardioplegia bloodcircuit and proper pump loading and occlusion of the second pump; andselecting the suction circuit test mode of the control unit to test forleaks in the suction circuit and proper pump loading and occlusion ofthe third pump.

DETAILED DESCRIPTION

FIG. 1 illustrates a cardiopulmonary bypass system embodiment of thepresent invention.

FIG. 2A illustrates one embodiment of a disposable assembly for use inthe system embodiment of FIG. 1.

FIG. 2B illustrates the disposable assembly of FIG. 2A

FIG. 3A is a schematic diagram illustrating the interface betweencomponents of the disposable assembly and component interface regionembodiments of FIGS. 2A and 2B, respectively.

FIG. 3B is a schematic diagram illustrating the interface betweencomponents of an alternate embodiment of a disposable assembly and acorresponding alternate embodiment of a component interface region.

FIG. 4 is a perspective view of the component interface region of theembodiment of FIG. 3A showing the cartridge, valve, arterial filter, andsensor interfaces.

FIGS. 5A and 5B are perspective views of the venous entry module ofFIGS. 3A and 3B; FIGS. 5C and 5D perspective views of the mountingbracket for the module of FIGS. 5A and 5B; FIG. 5E is a sectional viewof the module of FIGS. 5A and 5B; and FIG. 5F is a cross sectional viewalong line F-F of the view of FIG. 5E.

FIGS. 6A to 6E are views of the venous line clamp.

FIGS. 7A and 7B are views of the venous reservoir bracket/mount

FIGS. 8A to 8E are views of the oxygenator mount/interface.

FIGS. 9A to 9F are views of the tubing clips.

FIGS. 10A to 10D are views of the cartridge cam locks and tabs.

FIG. 11 is a block diagram of an alternative embodiment wherein thevenous reservoir is connected to a vacuum source for use in vacuumassisted drainage procedures.

FIG. 12 is a functional diagram of the continuous level sensor used tomeasure fluid level in the venous reservoir.

FIG. 13 is a front perspective view of cartridge 120.

FIG. 14 is a front plan view of cartridge 120.

FIGS. 15 and 16 are right and left side views, respectively, ofcartridge 120.

FIGS. 17 and 18 are top and bottom views, respectively, of cartridge120.

FIGS. 19A and 19B are back plan and back perspective views,respectively, of cartridge 120.

FIG. 20A is a cross-sectional view of cartridge 120 taken along line A-Aof FIG. 19A.

FIG. 20B is an enlarged view of detail B of FIG. 20A.

FIG. 21 is a cross-sectional view of cartridge 120 taken along line BBof FIG. 19A.

FIG. 22 is a back plan view of cartridge 120 with the flexible backlayer removed.

FIGS. 23A, 23B, 24A and 24B are partial views of a valve station incartridge 120.

FIG. 25 is a block diagram of the system architecture of the bloodperfusion system of the present invention.

FIG. 26 illustrates a schematic block diagram for the gas circuit shownin FIG. 25.

FIGS. 27 to 33 illustrate various operational examples of one embodimentof the system user interface 50. In particular, FIG. 27 illustrates thethree display regions of display 54 of the user interface.

FIGS. 28A-28F illustrate a variety of alarm and status messagesdisplayed in the first region of display 54.

FIG. 29 illustrates information sets displayed in the second region ofdisplay 54.

FIGS. 30A-30L illustrate various context-driven information sets andcorresponding context-driven user control options displayed in the thirdregion of display 54.

FIGS. 31A-31F, FIGS. 32A-32E and FIGS. 33A-33F illustrate variousfeatures of context-driven portion 243.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is an integrated vertical perfusion system. Themain components of the system are a console which houses the variouspumps, control circuitry, sensors and other nondisposable hardware, anda disposable assembly which connects to and interfaces with the console.The disposable assembly includes all of the disposable components usedin the extracorporeal blood circuit including, for example, a venousreservoir, a blood oxygenator, a heat exchanger and an arterial bloodfilter, as well as the tubing which connects the various components andwhich forms the extracorporeal blood flow path. The disposable assemblyalso includes a dedicated disposable cartridge which provides a primaryinterface between the disposable assembly and the console. The cartridgeis provided with multiple fluid flow paths through which the variousfluid circuits of the system flow. Sensors which interface with thefluid flow paths monitor certain characteristics of the system such aspressure, temperature, fluid level and the presence of bubbles invarious locations in the system. These characteristics provide anindication of whether the system is operating within acceptable ranges.Should these monitored characteristics deviate from acceptable rangesthe system is provided with feedback control features which cause thesystem to automatically return pressure, flow, and fluid levels back tosafe and acceptable ranges. After any deviation, the system will alertthe user and go into a safe mode if necessary/appropriate. The systemwill facilitate any required intervention by the user to return to safeand acceptable ranges.

The perfusion system of the present invention will now be described. Forpurposes of clarity an overview of the system will first be provided.Then the various components and features of the system will be describedincluding the disposable assembly and component interface, the systemcontrol, the user interface and an operational summary of the perfusionsystem.

I. Perfusion System Overview

FIG. 1 illustrates a perfusion system 1 for use during cardiopulmonarybypass surgery. The system comprises one embodiment of various aspectsof the present invention. Other applications and embodiments of theinventive aspects will be apparent to those skilled in the art.

The system 1 comprises a console or control unit 10 and a disposableassembly 100. Disposable assembly 100 is best seen in FIG. 2A whichshows the disposable assembly prior to attachment to control unit 10. Inthe illustrated embodiment, control unit 10 is “left-handed,” therebypermitting placement in an operating room so that it allows a user(e.g., perfusionist) to visually monitor the disposable assembly 100when interfaced with control unit 10 during operations, and to readilymaintain a direct line-of-sight with a head surgeon who is located in asterile surgical field surrounding a patient table (not shown). In thisregard, and by way of example only, control unit 10 is provided withwheels 5 and may be oriented at an angle relative to the patient table,as desired. As will be appreciated, control unit 10 may also be designedto be “right-handed” or universal.

Control unit 10 includes various sensors and mounting hardware forsupportably receiving and/or operatively interfacing with disposableassembly 100. More particularly, an upper component interface plate 12shown in FIG. 4 includes a cartridge interface region 20 for receiving acartridge 120 which forms a part of disposable assembly 100. Thecartridge interface region 20 includes various sensors for monitoringparameters of fluid flowing through the cartridge 120 during use as willbe explained in more detail hereafter. Further, control unit 10 includesadditional sensors for monitoring fluid parameters and various valvesfor controlling the flow of fluid through disposable assembly 100.

Control unit 10 includes a plurality of vertically “stacked” roller pumpassemblies 31-36. Each pump assembly comprises a rotatable control knob31 a-36 a and a pump information display 31 b-36 b, respectively.

The control unit 10 further includes one or more embedded processor(s)and a user interface 50 having a main display 54, user control knob 52,and a back up display 55. User interface 50 may be incorporated into themain housing of control unit 10 or may be provided in a separate housing51 that it can be selectively interconnected at a desired height andangular orientation relative to an outboard pole 11 or other pole ormounting bracket located in a desired position on control unit 10 suchas shown in FIG. 1. As will be further described, main display 54 andbackup display 55 of user interface 50 may be provided with variousgraphic user interface (GUI) features, including touch-screencapabilities, which together with user control knob 52 may beselectively employed with the embedded processor(s) to establish/modifyvarious settings for monitoring and controlling various parameters in acardiopulmonary bypass procedure.

In general, set-up of the system 1 entails removal of disposableassembly 100 from sterile packaging, e.g., a disposable tray, andpositioning of the various components of the disposable assembly 100relative to corresponding interfacing components of control unit 10 aswill be discussed in more detail hereafter. In general, three primaryfluid flow circuits are defined by the disposable assembly 100: a venouscircuit (i.e., for receiving venous blood from a patient), an arterialcircuit (i.e., for returning oxygenated blood to a patient) and acardioplegia circuit (i.e., for delivery of cardioplegia to a patient).The arterial and venous circuits may be combinatively referred to as thearterial-venous, or “AV” circuit. Secondary circuits defined bydisposable assembly 100 include two suction circuits (i.e., forselective suctioning of fluids from a patient by medical personnel), anda vent circuit (i.e., for venting accumulated blood or fluid from apatient's heart or vasculature). Another circuit comprising a fluidmanagement or priming circuit is used prior to bypass to primedisposable assembly 100. As will be further described, for flow controlpurposes through the fluid circuits, positioning of the disposableassembly 100 on control unit 10 includes the placement of various loopedtubing lines within pump assemblies 31-36 and positioning of varioustubing lines into various valve assemblies on control unit 10.

Additionally, for monitoring various parameters within the fluidcircuits, the cartridge 120 and various tubing lines and othercomponents of disposable assembly 100 are positioned in operativerelationship to various pressure, temperature, bubble, fluid level,hematocrit, oxygen saturation and other sensors included in control unit10. Further, an oxygenation device and one or more heat exchangersincluded within disposable assembly 100 are connected to gas and/orfluid inlet/outlet ports on control unit 10. After initial connectionsare made between the disposable assemblies and control unit 10, thevarious fluid circuits defined by the disposable assembly 100 are primed(i.e., filled with liquid to remove air), according to predeterminedprotocols. Thereafter, various tubing lines may be interconnected to apatient to provide for the flow of fluids to/from the patient anddisposable assembly 100.

II. Disposable Assembly

One embodiment of the disposable assembly 100 is shown in FIGS. 2A and2B. Disposable assembly 100 comprises various extracorporeal bloodcircuit components interconnected by tubing to create a blood flow path.FIG. 2A is a view of disposable assembly 100 before it is interfacedwith control unit 10. FIG. 2B is similar to FIG. 2A except that thetubing has been removed to more clearly show the disposable componentsof the assembly. These disposable components include disposablecartridge 120, venous entry module 108, pre-bypass filter 168, venousblood reservoir 106, a combined oxygenator and heat exchanger 112, anarterial blood filter 118 and tubing clips 111 a-111 f. Note thatalthough the oxygenator and heat exchanger are shown as an integratedunit, separate devices could be used as is known in the art. The venousentry module 108, cartridge 120 and tubing clips 111 are unique to theperfusion system of the present invention and are discussed in moredetail hereafter.

III. Hardware Interface and Mounting Assemblies

Control unit 10 is provided with various structural elements includingline clamps, sensors and mounting brackets for interfacing withcomponents of disposable assembly 100. Many of those sensors andinterfacing structures are located on upper component interface plate 12as seen in FIG. 4. Interface plate 12 includes a cardioplegia-valvetubing block 195. Tubing block 195 includes a cardioplegia air bubblesensor 158, a cardioplegia temperature sensor 153 and a motorizedcardioplegia line valve 96. Arterial valve tubing block 196 includes anarterial line air bubble sensor 126, arterial temperature sensor 88, anda motorized arterial patient line valve 92. Venous entry module mountingbracket 550 includes oxygen saturation-hematocrit standardizationsurface 83, oxygen saturation-hematocrit optical sensor 85 and a venoustemperature sensor 81. Interface plate 12 includes a motorizedpre-bypass filter valve 95 positioned above venous line clamp 46 andpre-bypass filter mount 70. Located at the bottom portion of plate 12 isan arterial filter mounting arm 760.

Upper component interface plate 12 includes a disposable cartridgeinterface region 20. Interface region 20 includes those components ofcontrol unit 10 which interface directly with cartridge 120. Cartridgemounting assembly 21 is used to secure the cartridge to region 20 in amanner discussed hereafter with regards to FIGS. 10A-10D. Region 20includes numerous pressure sensors for sensing line pressure in variouscircuit locations. These sensors include venous reservoir pressuresensor 89, first suction pump pressure sensor 40, second suction pumppressure sensor 42, vent pump pressure sensor 44, arterial line pressuresensor 14, and cardioplegia line pressure sensor 18. Each of thesepressure sensors function in the same manner except that the sensors inthe suction circuits sense negative pressure. Each sensor includes aload cell in control unit 10 and a load cell stem or cylindermagnetically coupled thereto (not shown). The load cell stem is alignedwith the cartridge at the location pressure is to be sensed. Pressureaffects the vinyl backing of the cartridge causing a force to be exertedagainst the load cell stem. This force is converted to an electricalsignal by the load cell. This electrical signal is then converted to apressure by a microprocessor. An example of such a pressure sensor isdescribed in U.S. Pat. No. 5,676,644 (Toavs et al.) which isincorporated herein by reference.

A plurality of solenoid valve plungers are also included within region20. These valve plungers interface with complimentary valve structureswithin cartridge 120 to open and close valves in various fluid circuitswithin cartridge 120. These valve assemblies include cardioplegia bubbletrap purge valve 404, vent pump to sequestration reservoir valve 402,vent pump to venous reservoir valve 403, low flow purge valve 405, highflow purge valve 406 and sequestration reservoir drain valve 401.Additional valve assemblies could be included. For example, valveassemblies could be included from the suction pump to sequestrationreservoir and/or suction pump to venous reservoir (not shown).

Cartridge interface region 20 includes several components whichinterface directly with a sequestration reservoir located withincartridge 120. First and second sequestration level sensors 320 and 322are used to monitor the fluid level in the sequestration reservoir. Adefoamer push bar 790 is used to apply pressure to a defoamer within thesequestration reservoir to ensure that fluid which enters thesequestration reservoir is caused to pass through the defoamer. Means isprovided in control unit 10 for bringing the cartridge 120 intoautomatic operative engagement with the various components in interfaceregion 20 by advancing such components through plate 12 into contactwith the cartridge.

At the upper portion of cartridge interface region 20 are motorizedpriming solution (or other solution) bag line valves 98 and cardioplegiacrystalloid bag line valves 99. Water connections 147 a and 147 b areprovided for connecting to a cardioplegia heat exchanger. Waterconnections 147 a and 147 b are designed to mate with ports 149 a and149 b on cardioplegia heat exchanger 148 in a manner similar to thatwhich will be described hereafter with respect to the water connectionsmade to heat exchanger 505 shown in FIGS. 8A-8E

Control unit 10 includes additional structural elements for interfacingwith disposable assembly 100. For example, the structure of the venousentry module 108 and the mounting bracket with which it is attached tocontrol unit 10 are shown in FIGS. 5A-5F. The structure and operation ofthe venous line clamps 46 and the mounting bracket for the pre-bypassfilter 168 are shown in FIGS. 6A-6E. The mounting bracket for the venousreservoir is shown in FIGS. 7A-7B. The mounting hardware for thecombined oxygenator/heat exchanger 112 is shown in FIGS. 8A-8E. Themounting hardware for the arterial filter 118 is shown in FIGS. 1 and 4.The manner in which cartridge 120 is mounted and interfaced with controlunit 10 is shown in FIGS. 10A-10D. Finally, the structure of tubingclamps 111 a-111 f is shown in FIGS. 9A-9F. A discussion of thesecomponents and their mounting and interface with control unit 10follows.

Although certain sensors, valves, etc., are packaged together in blocksin this embodiment, they could be provided as individual components orcombined together in any variety of integrated assemblies or in onecommon assembly.

1. Venous Entry Module

The venous entry module 108 is a unique component which allows multiplefunctions to be accomplished within a single circuit component. Thestructure and features of the venous entry module can best be understoodwith reference to FIGS. 5A and 5B. The manner in which the venous entrymodule is mounted and interfaced with control unit 10 is shown in FIGS.5C-5F.

With particular reference to FIGS. 5A and 5B which are perspective viewsof the top and bottom portions of the venous entry module it can be seenthat the venous entry module has inlet and outlet ports 530 and 532,respectively, which may be barbed. Housing 534 defines a lumen orconduit between the inlet and outlet ports which comprises the primaryflow passage for venous blood entering reservoir 106. A secondary flowport 536 is provided allowing the flow through the venous entry moduleto be diverted through the pre-bypass filter during priming of thedisposable assembly 100 as described more fully hereafter. Housing 534is also provided with sampling/infusion fluid addition/removal ports538, 540 and 542. These ports are connected to stopcock valves 539, 541and 543, respectively. These valves allow access to the venous line forthe addition of medication or fluids or removal of blood. For example,these valves allow a venous blood sample to be taken, allow fluids ordrugs to be infused during the bypass procedure, allow blood to beremoved for pre-donation sequestration prior to the procedure, and allowfluid to be added at some later point in the procedure. Mounting tabs544 and 546 on the side portions of housing 534 are located and sized toprovide a handhold for easy loading and to ensure proper positioning ofthe venous entry module in upper and lower mounting clips 548 and 552 ofmounting bracket 550 as shown in FIGS. 5C and 5D.

As shown in FIGS. 5B and 5C, housing 534 includes an oxygensaturation-hematocrit sensing window 554 and a temperature sensingwindow 556. Window 554 is aligned with optical sensor 85 on mountingbracket 550 so that hematocrit and oxygen saturation of the venous bloodflowing through the venous entry module can be measured. The manner ofsensing oxygen saturation-hematocrit is described in detail in U.S. Pat.No. 5,356,593 (Heiberger et al.), the entirety of which is incorporatedherein by reference. Window 556 is aligned with infrared temperaturesensor 81 to allow the temperature of the venous blood to be monitored.This temperature sensor is of conventional design and need not bedescribed in detail herein.

As best seen in FIGS. 5C and 5D the venous entry module is held in placein clips 548 and 552 by arms 548 a, 548 b, 552 a and 552 b. FIG. 5E is afront view of venous entry module 108 in bracket 550. FIG. 5F is asectional view taken along line F-F of FIG. 5E. The distance between theadjacent arms is slightly less than the outer dimension of the portionof the venous entry module positioned between the arms. Therefore, thevenous entry module is snap fit into bracket 550 and held by theadjacent arms. Bracket 550 includes a block 558 having a sliding portion560. Sliding portion 560 is spring loaded by virtue of spring 559 actingon stationary surface 561. Portion 560 includes a lower surface to whichis mounted standardization surface 83. During power up prior toinsertion of the venous entry module standardization surface 83 ispositioned over sensor 85 to allow the sensor to automaticallystandardize at power up. The light reflects off the standardizationsurface which allows the device to standardize. As the venous entrymodule is installed, the sliding portion moves out of the way so thatwindow 554 is positioned over sensor 85.

2. Pre-Bypass Filter and Venous Line Clamp

As noted above, the component interface region includes a venous lineclamp assembly (VLC) 46 for receiving tubing line 104 therewithin and abracket for mounting the pre-bypass filter to control unit 10. Thetubing size of the portion of line 104 between VLC 46 and venousreservoir 108 is preferably larger in diameter than the portion from thepatient to VLC 46. For example, the portion from the patient to VLC 46may be a one-half inch line while the portion from the VLC to the venousreservoir may be five-eighth inch. In general, VLC 46 is provided tocontrol the passage of venous blood from a patient to the venousreservoir 106 during bypass procedures. FIGS. 6A-6E illustrate oneembodiment of a VLC 46, which comprises a housing 71 for receivingvenous tubing line 104 through a slot 72 provided in the housing 71. Alid 73 may be hingedly interconnected to housing 71. Housing 71 includesa bracket 70 into which pre-bypass filter 168 may be secured. Bracket 70is substantially cylindrically shaped and forms slightly more than 180°of the circumference of a cylinder. The dimensions of this cylindricalconfiguration are chosen so that the pre-bypass filter can be snap fitinto the bracket and held without further attachment. A lid latch 74 maybe interconnected to housing 71, wherein a lip portion 74 a is adaptedfor selectively retaining lid 73 in a closed condition relative tohousing 71. As will be appreciated, when lid 73 is in such a closedcondition, a venous tubing line 104 may be retained within the slot 72of the housing 71.

The VLC 46 further includes a stepper motor 75. One end of a lead screw76 may be positioned in the stepper motor 75 and the other end of leadscrew 76 may be interconnected to a plunger 77, wherein the steppermotor 75 may be selectively operated for advancement/retraction ofplunger 77. The plunger 77 is sized and oriented to pass through anopening in the back of the housing 71, wherein selective operation ofthe stepper motor 75 allows the plunger 77 to be advancedacross/retracted from the slot 72 passing through housing 71. By virtueof such selective ability to position plunger 77, the VLC 46 providesfor the selective occlusion of a tubing line 104 positioned within theslot 72 housing 71. More particularly, when tubing line 104 ispositioned through slot 72 and lid 73 is secured in a closed position bythe latch 74, actual advancement of plunger 77 by stepper motor 75 willcause the tubing line 104 to be pinched between plunger 77 and lid 73 soas to occlude the tubing line 104 to a desired, selective extent. Thelid 73 can be opened at anytime, anywhere from the venous line clampbeing fully open or closed. This allows removal of the venous line inthe event of a failure so it can be manually clamped. The lid 73 is alsoclear so the user can verify venous line clamp actuation and open/closedstatus. In order to facilitate calibration at VLC 46 (e.g., toaccommodate varying wall thickness in tubing line 104), VLC 46 mayfurther include an optical encoder 78, wherein a calibration proceduremay be carried out to determine the desired positioning of lead screw 76for a given procedure.

3. Venous Reservoir

The mounting assembly of venous reservoir 106 is shown in FIGS. 7A and7B. FIG. 7A is a perspective view of reservoir mounting bracket 602spaced from reservoir 106 prior to reservoir 106 being inserted intobracket 602. FIG. 7B is a perspective view of reservoir 106 attached tomounting bracket 602. For purposes of illustrating clearly the mountingstructure mounting bracket 602 is shown detached from control unit 10.During use it will be understood that bracket 602 is affixed to controlunit 10 in the position shown in FIG. 1.

As shown in FIGS. 7A and 7B mounting bracket 602 includes flexible arms604 and 606. The arms are provided with grooves 606 a and 604 a whichare shaped to received the circumferential edge 107 a of a lid 107 atthe top of reservoir 106. Reservoir 106 is mounted by sliding edge 107 ainto grooves 604 a and 606 a. Flexible arms 604 and 606 are slightlycurved and extend more than 180° around edge 107 a so that reservoir 106is held in a snap fit configuration by arms 604 and 606.

4. Oxygenator/Heat Exchanger

The mounting assembly for the combined oxygenator/heat exchanger isshown in FIGS. 8A-8E. FIG. 8A is a perspective view of oxygenator/heatexchanger 112 separated from mounting bracket 500. FIG. 8B is a backperspective view of oxygenator/heat exchanger 112 showing the locationof the various gas and water inlet and outlet ports. FIG. 8C is a frontview of mounting bracket 500 showing the location of gas and waterconnections. FIG. 8D is a front view of the oxygenator/heat exchanger112 mounted on bracket 500 and FIG. 8E is a cross-sectional view takenalong line E-E of FIG. 8D.

In the embodiment shown in FIGS. 8A and 8B mounting assembly 500includes a lower portion 501 which is configured to receive the heatexchanger. Portion 501 has a heat exchanger receiving slot 502 withlower grooves 502 a and 502 b. Between grooves 502 a and 502 b is aledge 503 for retaining the heat exchanger. Slotted side portions 504 aand 504 b are configured to receive heat exchanger mounting tabs 505 aand 505 b. Thus, to mount oxygenator/heat exchanger 112 on lower portion501 the heat exchanger 505 is inserted in slot 502 with heat exchangerstabs 505 a and 505 b above slotted side portions 504 a and 504 b. Theheat exchanger is then moved in a downward direction so that the heatexchanger tabs mounting 505 a and 505 b are received in slots 504 a and504 b, respectively, and so that retaining ledge 503 is positionedbetween the heat exchanger and the oxygenator.

As best seen in FIG. 8C mounting assembly 500 includes gas fittings 508a and 508 b for providing oxygen-containing gas to the oxygenator andremoving carbon dioxide therefrom. Additionally fittings 509 a and 509 bare provided for circulating heating/cooling fluid through the heatexchanger. Motorized oxygenator vent line valve 507 is provided toreceive vent line 105 connected between the oxygenator and venousreservoir. Loading of the vent line into the vent line valve isfacilitated by vent line loading element 506 which is slotted to receiveand route the vent line through slots 507 a and 507 b of valve 507.Valve 507 includes a roller 525 eccentrically mounted on a rotatingmember (not shown) that, when rotated, causes the roller to pinch thetubing to occlude or partially occlude flow.

Fittings 508 a, 508 b, 509 a and 509 b are tapered at their end portionsand have O-rings 512, 513, 514 and 515 disposed thereabout. The taperedends of fittings 508 a and 508 b are designed to sealingly engage gasinlet and outlet ports 518 a and 518 b on the oxygenator while taperedfittings 509 a and 509 b are designed to sealingly engage water inletand outlet ports 519 a and 519 b of the heat exchanger. Mountingassembly 500 is designed to automatically engage the tapered fittingswith the corresponding ports of the oxygenator and heat exchanger.Mounting assembly 500 includes a stationary face plate 510 and amoveable carriage member 511. The carriage member may be advanced orretracted with respect to face plate 510 by operation of a stepper motor516 acting on a lead screw 517 as shown in FIGS. 8A and 8E.

The carriage member rides on guide rods (not shown) which are pressedinto the face place. Forward and reverse limit switches (not shown) areused to indicate when the carriage member is forward or fully retracted.The carriage member must be retracted to load an oxygenator into thebracket.

As best seen in FIG. 8E, the water and gas fittings are spring loadedalong the fitting axes and able to move freely perpendicular to theaxes. All of the fitting axes are parallel to allow them all to engagethe oxygenator or heat exchanger in a single motion. Each fitting ismounted in a flanged bushing, such as 520 a, 520 b, and 520 c. Theinside diameter of the bushing is larger than the outside diameter ofthe fitting at the inserted section, so that the fitting can move freelyinside the bushing.

Axial motion of the fitting relative to the bushing is prevented in onedirection by a flange on the fitting (i.e., 521 a, 521 b, 521 c) whichmates with a flange on the bushing. Motion in the opposite direction islimited by a retaining ring (not shown) attached to the fitting whichcollides with the back surface of the bushing.

The fitting assembly is spring loaded towards the mating port with acompression spring (i.e., 522 a, 522 b, 522 c). The compression springexerts a force on the back side of the bushing flange. The opposite endof the spring pushes against a surface of the fitting base which isfixedly attached to the carriage member.

The heat exchanger water fittings are machined from a single piece ofmaterial. However, the gas supply fitting and scavenge line fitting aremade from an assembly of a machined fitting piece and a standard pipenipple. The pipe nipple rides inside the flanged bushing. The backportion of the gas fitting rides against the flange face of the flangedbushing.

The gas and water fittings are connected to the carriage member so thatthey are caused to advance or retract by movement of the carriagemember. Thus, once the heat exchanger has been mounted on lower portion501 the connections for water and gas may be automatically made byadvancing the carriage so that the fittings are caused to engage withthe corresponding ports on the oxygenator and heat exchanger.

5. Arterial Blood Filter

The manner in which the arterial blood filter 118 is mounted andinterfaced with control unit 10 can best be understood with reference toFIGS. 1 and 4. Blood filter 118 held by mounting arm 760. Arm 760extends from a lower portion of upper component mounting plate 12. Arm760 includes a first straight portion 761 and a second flexible curvedportion 762. Curved portion 762 is provided with a groove 762 a which issized to accommodate an outwardly extending lip on the cover of filter118. Curved portion 762 is substantially semicircular and extendsslightly past 180°. Therefore, the outwardly extending lip may besnapped into place in groove 762 a so that the arterial filter is heldsecurely by arm 760.

A rotating assembly means 763 is activated during the priming ofdisposable assembly 100 to cause arm 760 along with arterial filter 118to rotate 180°. This facilitates removal of air bubbles from filter 118.By flipping the filter 180° during an automated priming procedure, eventhough priming fluid follows an antegrade path through the filter fromthe inlet to the outlet the direction is from bottom to top. Inconventional priming techniques retrograde flow of priming fluid fromoutlet to inlet is required in order to get bottom to top flow. Inconventional systems, this requires extra set up for priming of thefilter and a bypass line with extra ports.

In order to enhance the efficiency of bubble removal during primingportion 761 is angled about 221/2° from the horizontal and portion 762is angled about 45° from the horizontal to allow air to rise to thearterial filter purge outlet. This results in filter 118 being held atan angle during bypass as shown in FIG. 1. However, during the primingprocedure discussed in more detail hereafter, when arm 760 is rotated180° the angled portions 761 and 762 cause filter 118 to be held suchthat its longitudinal axis is perpendicular to an intersectinghorizontal plane. This allows priming fluid (and bubbles) to flowvertically and upwardly through the filter from the inlet to the outletwhich lessens the chance of bubbles being trapped within the filterduring priming.

6. Tubing Clips

As indicated hereinabove, clips 111 a-f may be provided to definepredetermined U-shaped configurations for tubing loops 110, 132, 140,178, 180, and 190, respectively. One embodiment that may be employed fortubing clips 111 a-f is illustrated in FIGS. 9A-9F. As shown, theexemplary tubing clip 700 may include a central body member 702 havingtwo tubing connector wings 704 extending from opposing sides of thecentral body member 702. Each of the tubing connector wings 704 maydefine a longitudinally-extending J-shaped channel for receiving atubing length therethrough. One or more wedge-shaped members 706 may bedisposed within each of the J-shaped channels of the tubing connectorwings 704 for retaining tubing positioned through the channels.Alternatively, the tubing may be glued within the channels to preventmovement. The tubing connector wings 704 may be oriented at an anglerelative to the main body member 702 so that the center axis of each ofthe channels are angled. This allows the tubing entering the pump toconform to the pump raceway. This allows a desired tubing loopconfiguration to be formed when the clip is applied to the tubing thusfacilitating the loading of the tubing loop into one of the pumpassemblies 31-36. The central body member 702 may include a projectinggrip tab 708 contoured in an hourglass configuration to facilitatehandling and placement of the clip 700 in a pump assembly. In the latterregard, the central body member may include a hollow bottom portion tomatingly fit over a projection provided on a pump assembly. The clip 700may be integrally formed (e.g., via molding, etc.). The tubing clips maybe color coded to match corresponding color coding on control unit 10 toensure correct placement of the pump loops.

7. Cartridge

The perfusion cartridge 120 allows for automation of the perfusionsystem because the compact and standardized format of the positioning ofthe passageways in the cartridge 120 allows computer controlled sensorsand actuators to interact with the cartridge 120. It is important thatthe interface between cartridge 120 and control unit 10 be precise andsecure. The manner in which cartridge 120 is mounted on control unit 10is shown in FIGS. 10A and 10D. In this regard, cartridge mountingassembly 21 secures the perfusion cartridge 120, as shown in FIG. 10A,to cartridge interface region 20. Interface region 20 containstemperature and/or pressure sensors located to interface mount withsensor stations on the cartridge 120. Region 20 also contains valveplungers positioned to interface with valve stations on the cartridge.

FIG. 10A shows cartridge 120 contained within mounting assembly 21.Although interface region 20 and mounting assembly 21 are part of uppercomponent interface plate 12 for purposes of illustration and tofacilitate an understanding of the mounting of cartridge 120 onlymounting assembly 21, interface region 20 and cartridge 120 are shown inFIGS. 10A-10A-D.

FIG. 10C shows cartridge 120 spaced apart from mounting assembly 21. Tofacilitate mounting cartridge 120 is provided with mounting tabs 121.Assembly 21 has openings 115 which expose slots 117 which are sized tosecurely accept tabs 121 of cartridge 120. To load cartridge 120 intomounting assembly 21 tabs 121 are aligned with openings 115. Thecartridge is then moved in the direction of interface region 20 untilthe tabs 121 align with slots 117. Once so aligned the cartridge ismoved downward in the direction of arrow 131 (FIG. 10D). This secureseach of the tabs in corresponding slots and holds cartridge 120 againstinterface region 20.

To insure that cartridge 120 is properly positioned with respect tointerface region 20 and that it maintains the proper position during thebypass procedure a positioning mechanism is provided. As shown in FIG.10B, which is an enlarged portion of FIG. 10A, motorized cardioplegiacrystalloid valves 99 include an angled bottom surface 124. Whencartridge 120 is loaded into mounting assembly 21 valves 99 areretracted so that they do not extend beyond the surface of interfaceregion 20. Once cartridge 120 has been loaded into mounting assembly 21the continuing set up of the system results in valves 99 being advancedpast the surface of interface region 20 until they reach the positionshown in FIG. 10B. As the valves advance angled surface 124 abutsagainst surface 127 on cartridge 120 resulting in a downward pressurebeing exerted on cartridge 120. This ensures that cartridge 120 is inits proper position and that it does not move during the bypassprocedure.

Valves 99 are roller valves similar in structure to valve 507 andinclude rollers 101 and slots 99 a and 99 b. Valves 98 are roller valvessimilar to valves 99 although the specific structure is not shown inFIG. 10B. The cartridge includes tubing retainers 102 a-d which hold thecrystalloid solution and priming lines in the proper alignment forloading to valves 98 and 99.

IV. Functional Integration of Disposable Assembly and Control Unit

FIGS. 3A and 3B are schematic diagrams of different embodiments of thefunctional interface between disposable assembly 100 and control unit10. The embodiment of FIG. 3A relates to the functional interface of asystem using the cartridge 120 as disclosed in the drawing figuresherein. The embodiment of FIG. 3B relates to a version of the perfusionsystem using a cartridge modified in a manner disclosed herein.

As shown in FIG. 3A, disposable assembly 100 includes a number of tubinglines that either alone or in combination with the integral passagewaysof cartridge 120 define a number of fluid circuits. In particular,tubing line 104 extends from a cannula assembly at a distal end (notshown) to a venous reservoir 106 via a venous entry module 108. Aspreviously described the venous entry module includes sensing windows554 and 556 which interface with oxygen saturation-hematocrit sensor 85and temperature sensor 81 located in cartridge interface region 20.These sensors can provide feedback for use in various control circuits.For example, a user can set alarm limits which provide an alarm if a lowoxygen saturation and/or hematocrit condition exists. Further, if oxygensaturation is low the system can be set to automatically increase thespeed of the arterial blood pump 31 an incremental amount and/orautomatically adjust the gas blender to increase gas flow or F_(i)O₂concentration through the oxygenator, until the condition is corrected.Additionally, when blood is detected as flowing through the venous entrymodule by sensor 85 all pre-bypass activity is automatically inhibited(i.e., pre-bypass filter valve 95 is closed so that flow through thepre-bypass filter is discontinued). The venous entry module also allowspre-donation blood to be collected for reinfusion to the patient at theend of the procedure through a large bore stopcock 543 on the front ofthe venous entry module. Pre-donation is the collection of a portion ofthe patients blood, usually about one liter but is based on calculatingwhat the patient can give up without lowering the hematocrit below somepredetermined value, as the blood first comes down the venous line. Thisblood is sequestered and usually reinfused back into the patient at theend of the procedure.

For purposes hereof, all components upstream of oxygenator 112collectively comprise the “venous circuit”. During a cardiopulmonarybypass procedure, tubing line 104 will transfer venous blood from one ormore of the large veins entering the heart (e.g., the venae cava) orother veins of a patient to venous reservoir 106. As described withrespect to FIGS. 6A-6E, the flow of venous blood though line 104 may beselectively regulated by a venous line clamp (VLC) 46. Flow may also beregulated by using a vacuum system interconnected to the venousreservoir 106 as discussed hereafter with respect to FIG. 11, or a pump(not shown) that regulates venous blood flow through line 104 upstreamof the venous reservoir 106. The VLC is an integral part in theautomatic control of the perfusion system. Once the bypass has beeninitiated the VLC is automatically kept open when arterial pump 31 isrunning. If pump 31 shuts down for any reason the VLC may automaticallybe closed by the system control. The VLC may be closed when the levelsensor in the venous reservoir senses that the reservoir is full.Additionally, the rate of flow of blood to the venous reservoir can becontrolled by the extent to which line 104 is occluded by the VLC. Thecontrol can be automatic such as a system initiated response due to ahigh blood level condition being sensed in the venous reservoir, or canbe manual through user settings at the user interface.

Tubing line 104 may be constructed from a clear, flexible tubing toallow for selective occlusion by the VLC 46 and to otherwise allow forvisual inspection of fluid passage therethrough by a user. In thisregard, the VLC 46 may include a transparent lid 73.

Reservoir 106 may be of a hard shell or soft, plastic construction, andmay be partially transparent with volumetric markings to facilitatevisual monitoring of volume content by a user during a bypass procedure.The reservoir 106 may include a gas vent at a top end thereof to allowfor the venting of any accumulated gas. Alternatively, the reservoir maybe sealed, and may further include a top port for interconnection with avacuum source for optional use in vacuum assisted venous drainageprocedures. The vacuum source may comprise a vacuum pump (e.g., withincontrol unit 10) or a regulator that may be selectively interconnectedwith a facility vacuum line.

FIG. 11 shows an alternative embodiment where reservoir 106 is connectedto a vacuum source for use in vacuum assisted drainage procedures. InFIG. 11, vacuum line 721 is attached to the vacuum port of venousreservoir 106, connecting the venous reservoir to the vacuum system. Thesystem comprises vacuum line 721 interconnected to float valve 722,hydrophobic filter 726, electronic vacuum regulator 727, and to anexternal vacuum source 728. The float valve 722 automatically closes toprevent fluid from entering the vacuum system in the event of a venousreservoir overflow. The hydrophobic filter 726 also prevents fluid frompassing further into the vacuum system. The electronic vacuum regulator727 provides continuously adjustable control of the vacuum level in thevenous reservoir as measured by vacuum sensor 725, and as discussedhereafter, can be activated to provide level control within the venousreservoir. Also incorporated in the vacuum circuit are positive pressurerelief valve 723 and excess vacuum relief valve 724. These valves willautomatically open if required to provide additional control to preventvacuum from exceeding a predetermined upper or lower limit.

The venous reservoir can be provided with a level sensor 87 as will bedescribed in more detail hereafter with respect to FIG. 12. The sensedlevel can be used to activate alarms at the user interface indicativeof, for example, full reservoir, empty reservoir, and low level. Thesensed level can also be used in the closed loop feedback control ofother parts of the perfusion system which affect the level of blood inthe reservoir. For example, the sensed level can be used to control thefluid level in the reservoir by controlling VLC occlusion, arterial pumpspeed or the amount of vacuum if the reservoir is vacuum assisted inorder to maintain, increase or decrease the reservoir volume or level asneeded to transfer fluid back and forth to the patient or maintain asafe reservoir level to prevent emptying.

A reservoir filter pressure sensor 89 is included in integral passageway164 in the embodiment of FIG. 3A. During bypass if suctioned cardiotomyblood is routed to the venous reservoir the reservoir filter can clog.This cardiotomy blood is gravity drained from the sequestrationreservoir and if the venous reservoir filter becomes clogged, pressurecan build. Sensor 89 senses the increased pressure from a clogged filterand provides an alarm on user interface 50. In the event of any alarm,the suction and vent pumps may be stopped and/or valve 401 may beautomatically closed, and/or valve 98 may be automatically closed.

Connected to the bottom end of reservoir 106 is an interconnect tubingline 110 which carries blood from venous reservoir 106 to an oxygenator112. Although referred to herein as oxygenator 112 it should beunderstood that the oxygenator may include an integral heat exchanger.As will be further described, the flow of blood through the interconnecttubing line 110 is selectively regulated by arterial pump 31. Tubingline 110 may include a clip 111 a as described with respect to FIGS.9A-9F for retaining a predetermined tubing length in a predeterminedu-shaped configuration for ready interface with the arterial pumpassembly 31. Further, such clip may be color-coded (e.g., red forarterial) and configured to facilitate ready pump interfaceidentification and clip placement during loading procedures.

Pressure sensor 84 may be provided to sense the pressure in tubing loop110 downstream of the arterial pump 31 and upstream of the oxygenatordevice 112. In this regard, the monitored pressure may be compared topredetermined minimum and maximum values. A monitored pressure below thepredetermined minimum value indicates that pump 31 may not be occludingtubing loop 110 as desired or may not otherwise be operating at a rateset by use of control 31 a, resulting in an alarm/indication atinterface 50. A monitored pressure that exceeds the predeterminedmaximum value indicates that the arterial circuit downstream of sensor84 may be undesirably occluded (e.g., partially or fully), and mayeffect automated stoppage or slow down of pump 31 and result in analarm/indication at interface 50.

Oxygenation device 112 is fluidly interconnected at its outlet port tooutlet tubing line 116 which is connected to the inlet of arterialfilter 118. Outlet tubing line 116 may be retainably positioned relativeto a bubble sensor 114 located on control unit 10. Bubble sensor 114serves several functions. First, if bubbles are detected an alarm may beactivated at user interface 50. Second, detected bubbles may cause anauto air shunt feature to be activated as described in more detailhereafter.

The embodiment of FIG. 3A includes an oxygenator vent tubing line 105from the oxygenator to the venous reservoir. Tubing line 105 passesthrough oxygenator vent valve 507. Vent valve 507 has several functions.First, it is automatically opened during priming to remove air from theoxygenator and is closed after a predetermined time. Second, it can bemanually opened by the user during bypass if, for example, the venousreservoir emptied causing air to enter the system necessitating that thesystem be reprimed or, repriming the oxygenator after oxygenatorreplacement.

Arterial filter 118 is designed to filter particles greater than apredetermined size (e.g., having a maximum cross-sectional thicknessgreater than 50 microns), and is fluidly interconnected to outlet tubinglines 122, 128, and 119 a. Outlet tubing line 122 is provided for thereturn of oxygenated blood to a patient via a cannula assembly at adistal end (not shown). Tubing line 122 may be retainably positioned ina bubble sensor 126 located on control unit 10. If bubbles are sensed bysensor 126 an alarm at user interface 50 will be activated.Additionally, a signal will be fed to the control unit 10 which willcause the arterial pump 31 to stop. The system is designed so thatanytime the arterial pump is stopped, purge valves 405 and 406 and thearterial patient valve 92 may be closed. It should be noted that anytimea detected alarm condition causes the system to automatically stop apump or close a valve that action can be overridden by the user at theuser interface.

In the event a user would like to draw a sample of the blood passingthrough arterial filter 118, a user may open a stopcock valve 310 or 311provided on cartridge 120. If the sample is to be taken from valve 310,either valves 405 or 406 must be open. For purposes ofhemoconcentration, a user may also manually open valve 310 or 311provided on cartridge 120 to provide for the flow of arterial bloodtherethrough. In this regard, the user may provide a separatehemoconcentrator unit (not shown) having inlet tubing connected tostopcock valve 310 or 311 and outlet tubing interconnected to a transferbag (not shown) or interconnected to an inlet port provided at venousentry module 108 or venous reservoir 106.

For purposes hereof, the noted components downstream from oxygenator 112through outlet tubing line 122 collectively, comprise the “arterialcircuit”. To facilitate priming procedures, tubing lines 104 and 122 maybe initially fluidly connected via a connector 175 which is removedafter priming and prior to cannula placement.

In order to monitor the temperature of the oxygenated blood returned toa patient, the upper component interface plate 12 may also includetemperature sensor 88 located in tubing line 122. Alternatively, thesensor 88 may be positioned for sensing temperatures at arterial filter118. The monitored temperature of returned blood is compared topredetermined minimum/maximum range values, wherein an alarm or otherindication (e.g., an indication of potential responsive action) can beprovided at user interface 50 upon the detection of out-of-rangeconditions. Similarly, valve assembly 92 may be included to receivetubing line 122 downstream of the bubble sensor 126, and may beselectively and automatically opened/closed to control the flow ofoxygenated blood through tubing line 122, including for example, closureboth during pre- or post-bypass procedures and when bubble sensor 126detects gaseous bubbles in the oxygenated blood during bypassprocedures.

Tubing lines 119 a and 119 b are provided for fluid flow from arterialfilter 118 to cartridge 120, and from cartridge 120 to reservoir 106,respectively. Adjoining integral passageways 309 a and 309 b areprovided in cartridge 120 to selectively receive fluid flowing throughtubing line 119 a. In order to control the flow of fluid throughpassageways 309 a and 309 b, cartridge interface region 20 includesinterface valve assemblies 405 and 406. When opened, valve 405 providesfor a relatively low flow rate through passageway 309 b. Valve 406provides for a relatively high flow rate through passageway 309 a whenvalve 406 is open. During bypass procedures, valves 405 and 406typically remain open and closed, respectively; provided pressure sensor14 senses a pressure greater than a predetermined minimum value. If apressure lower than the minimum value is sensed both valves 405 and 406automatically close in order to prevent air from being sucked from thevenous reservoir into the arterial filter. A user may selectively changethese states via user interface 50, as will be further described. Inorder to purge air from tubing line 116 and arterial filter 118 (e.g.,upon bubble sensing by bubble sensor 114), valve 92 may be closed (e.g.,automatically), and valves 405 and 406 may be opened (e.g.,automatically), wherein blood will flow through tubing line 119 a,integrated passageway spurs 309 a and 309 b, and tubing line 119 b intovenous reservoir 106 via an inlet port. Additionally, in the event thatair is detected in tubing line 122, valves 92 and 96 may be closed andvalve 404 opened so as to cause blood to flow retrograde from thepatient through tubing line 122 through filter 118, flow tubing line128, integral passageway 130 and ultimately through integral passageways164 and 308 for return to venous reservoir 106 through line 129. Itshould be noted that valve 406 may be selectively opened forrecirculation purposes or otherwise by a user.

As noted, arterial filter 118 is also interconnected to outlet tubingline 128, which in turn is interconnected with one end of an integralpassageway 130 defined within the cartridge 120 to provide the bloodsupply for the cardioplegia system.

Pressure sensor 14 is provided in cartridge interface region 20 formonitoring the fluid pressure within fluid passageway 130 and tubinglines 128 and 122 fluidly interconnected thereto. During cardioplegiablood delivery via tubing line 128 and pump 35, the monitored pressuremay be compared to a predetermined value to insure that an adequateblood delivery pressure is provided. If the pressure falls below apredetermined minimum value, pump 35 may be stopped and/or analarm/indication may be provided at user interface 50. Additionally, ifthe arterial blood circuit has become occluded, automated stoppage ofpump 31 may be provided and an alarm/indication may be provided at userinterface 50 if the pressure exceeds a predetermined maximum value.

Tubing line 128, cartridge passageway 130 and tubing loop 132 areprovided for the flow of blood therethrough for selective downstreammixture with a heart-arresting solution (e.g., a cardioplegiccrystalloid solution) and/or a substrate enhancing solution (e.g.,nutritional solution) in an integral passageway 142 of cartridge 120. Aswill be further described, tubing loop 132 interfaces with acardioplegia blood pump assembly 35 of component interface region 12 tocontrol mixture ratios. Tubing loop 132 may include a clip 111 b toestablish the desired u-shaped configuration for the pump interface, andthe clip may be color-coded (e.g., red) to facilitate ready loading.

Disposable assembly 100 further includes one or more spiked tubinglengths 133 for interconnection between one or more corresponding bags136 of a heart-arresting solution (e.g., crystalloid solution) and afluid passageway 138 integrally defined within cartridge 120. One ormore substrate enhancing solutions (not shown) may also be fluidlyinterconnected by spiked tubing lengths 133 to the integral passageway138 of cartridge 120. When multiple bags 136 are provided they maycontain solutions of different concentration and/or ingredients. Theuser is able to select the desired solution concentration by selectingat the user interface which one of valves 99 is opened. The user is ableto select a volume or time bolus of solution and the opened valve 99automatically closes when delivery is completed or interrupted such aswhen one or more of pumps 31, 35 or 36 is stopped. The user is also ableto manually select and deliver the cardioplegia solution.

Passageway 138 is interconnected to a tubing loop 140 that flowsheart-arresting or substrate enhancing solution out of and back into thecartridge 120 and interfaces therebetween with a pump assembly 36 oncontrol unit 10 that regulates the flow rate through the tubing loop140. Tubing loop 140 may include a clip 111 c to establish the desiredu-shaped configuration for pump interface, and the clip 111 c may becolor-coded to facilitate loading.

Integral passageway 142 is also interconnected to the above-mentionedtubing loop 132 for establishing a desired mixture between thecardioplegic crystalloid solution and blood pumped into the integralpassageway 142. In this regard, it should be appreciated thatcardioplegia provided to a patient may comprise predetermined (ordynamically adjusted) relative amounts of a heart-arresting solution(crystalloid) and blood, and may alternatively comprise only aheart-arresting solution (crystalloid), or alternatively comprise onlyoxygenated blood.

In this regard, a tubing line 146 is provided for the passage of acardioplegia solution out of the cartridge 120, through a cardioplegiaheat exchanger 148 and a bubble trap 152, and back into the cartridge120. In an alternate arrangement, heat exchanger 148 and/or bubble trap152 may be integrated into cartridge 120.

Of additional note, the embodiment of FIG. 3A includes a stopcock valve302 in fluid communication with the bubble trap 152 through which thecardioplegia mixture flows during operations. The inclusion of stopcockvalve 302 allows a user to selectively infuse drugs into thecardioplegia mixture. Further, stopcock valve 302 may be selectivelyemployed by a user for interconnection of an auxiliary pressure sensor(i.e., monitor the cardioplegia pressure) or it can be used to samplethe cardioplegia solution or can be connected to a hemoconcentrator (notshown). Relatedly, it is noted that the cartridge 120 in the FIG. 3Aembodiment also includes an added integral passageway 308 thatinterfaces with a corresponding valve assembly 404 provided in thecartridge interface region 20. More particularly, valve 404 can beselectively opened/closed in opposing or same relation to valve 96 in anumber of situations. For example, valve 96 may be closed and valve 404opened during priming so as to cause fluid flowing through integralpassageway 150 to flow through integral passageway 308 and into integralpassageway 164. Additionally, during cardioplegia delivery, if a userobserves a build-up of gas in bubble trap 152, a user may open valve404, thereby causing at least some fluid to be diverted through integralpassageway 308 into integral passage 164, thereby purging the air frombubble trap 152. If the fluid pressure is too low to effect purging,valve 404 may be automatically closed to prevent the introduction of airinto the circuit.

At its downstream end, tubing line 146 is connected from bubble trap 152to another integral passageway 150 of cartridge 120. In the embodimentdisclosed the bubble trap 152 and cardioplegia heat exchanger 148 arecombined in a single unit which is separate from cartridge 120 but thatfits into the cartridge and interfaces directly with control unit 10 atcartridge interface region 20. Bubble trap 152 may be equipped with abubble sensor (not shown) that, upon sensing bubbles would causecardioplegia purge valve 404 to open and cardioplegia patient valve 96to close thus routing the cardioplegia solution to the venous reservoirthrough line 164. Air bubbles may be manually purged from bubble trap152 by activation of a button (not shown) on user interface 50. Bubbletrap 152 may include a filter screen (e.g., a 200 micron screen) to trapparticulates and air and may include a vent (e.g., a one-way valve)having a hydrophobic membrane.

Pressure sensor 18 is provided in cartridge interface region 20 to sensethe pressure within passageway 150. During cardioplegia delivery themonitored pressure may be compared with a predetermined maximum value toidentify if the cardioplegia circuit has become occluded (e.g., whereinautomated stoppage of pumps 36 and/or 35 may be effected and analarm/indication may be provided at interface 50). Additionally, thepressure may be monitored during cardioplegia delivery to insure anadequate cardioplegia delivery pressure. In the event the monitoredpressure falls outside of user set limits an alarm/indication may beprovided at interface 50 and/or the speed of one or both of pumps 35 and36 is either increased or decreased in order to maintain the desiredpressure. For example, the user may set at the user interface a highpressure limit of 150 mmHg, a low pressure limit of 20 mmHg and acontrol point of 100 mmHg. By utilizing the monitored pressure as afeedback control parameter the system will automatically adjust thespeed of the pumps to maintain pressure at the control point. If thepressure exceeds for any reason the upper or lower limit an alarm isactivated at the user interface.

A temperature sensor 153 is provided in cardioplegia valve block 195 tomonitor the temperature of the fluid in line 156. High and lowtemperature alarm limits may be set by the user at the user interfaceand if those limits are exceeded an alarm is activated at user interface50.

Additionally, if the pressure sensed by cardioplegia line sensor 18 isbelow the minimum limit the system automatically causes either or boththe cardioplegia patient valve 96 and cardioplegia purge valve 404 toclose. This prevents retrograde air from being introduced into thecardioplegia circuit through patient tube line 156, cardioplegiasample/infusion valve 302 or cardioplegia purge line 308. Integralpassageway 150 is interconnected to tubing line 156 having a catheterassembly (not shown) at its distal end for the delivery of thecardioplegia mixture to a patient.

Tubing line 156 may be fluidly interconnected via tubing connector 175to tubing line 104 and 122 for priming purposes, wherein tubing line 156is disconnected from tubing connector 175 after priming. Tubing line 156may be retainably positioned in cardioplegia valve block 195 containinga cardioplegia patient valve 96, a temperature sensor 153, and a bubblesensor 158 provided in the upper component interface plate 12, asdescribed. If bubbles greater than an acceptable size are detected atsensor 158 the system automatically stops one or both of pumps 35 and 36and provides an alarm at user interface 50. For purposes hereof, theabove-described components that provide for the flow of blood fromtubing line 128 and crystalloid solution from bags 136, through tubingline 156, collectively comprise the “cardioplegia circuit”.

For priming purposes and/or adding blood or other solutions, disposableassembly 100 further includes one or more spiked tubing line lengths 160for interconnection between one or more bags 162 of priming fluid orother solutions and a fluid passageway 164 integrally defined withincartridge 120. An outlet of fluid passageway 164 is interconnected to afiltered inlet of reservoir 106. Relatedly, it is also noted that thedisposable assembly 100 includes a tubing spur 166 interconnected withthe venous entry module 108 of the component interface region for theselective passage of priming fluid therethrough during primingoperations. Further in this regard, tubing spur 166 includes apre-bypass filter 168 for filtering the priming solution to ensure thatparticles having a size greater than a predetermined value (e.g.,greater than 5 microns) are filtered from the system prior to theinitiation of bypass procedures. During priming flow is automaticallydirected through pre-bypass filter 168 by closing VLC 46 and openingpre-bypass filter valve 95. Since the pores of the pre-bypass filter arevery fine and would be clogged by blood, as soon as the presence ofblood is sensed at sensor 85 of the venous entry module valve 95 isclosed and the VLC 46 is opened thus routing the blood directly to thevenous reservoir 106.

For purposes of priming and for filtering in conjunction with priming,valve assembly 95 is provided to receive tubing line 166 for selectiveand automatic closure/opening. Similarly, valve assembly 96 is providedto receive cardioplegia tubing line 156 and is selectively andautomatically operable for opening/closure, including for example,automatic closure upon detection of gaseous bubbles in the cardioplegiamixture by bubble sensor 158. One or more valve assemblies 98 are alsoprovided in component interface region 12 for automatically andselectively controlling the flow of priming solution from one or morepriming solution bags 162 through tubing line(s) 160. Similarly, one ormore valve assemblies 99 are provided for selectively and automaticallycontrolling the flow of crystalloid solution from the one or morecrystalloid solution bags 136 through tubing line(s) 133.

The disposable assembly 100 also includes first and second tubingsuction lines 170 and 172, respectively, each of which areinterconnectable at their distal ends to corresponding suctioningdevices (not shown) for removing fluid from a patient surgical site. Thefirst and second tubing lines 170, 172 are initially plugged at the endto allow leak testing, occlusion testing of the suction pumps 32 and 34and testing to ensure that the pump loops are loaded in the pumps in thecorrect direction. Each of such tubing lines 170 and 172 areinterconnected to corresponding integral passageways 174 and 176,respectively, within the cartridge 120, which passageways are in turninterconnected with tubing loops 178 and 180, respectively.

Pressure sensors 40 and 42 are provided in cartridge interface region 20to monitor the pressures within suction tubing lines 170 and 172,respectively, which are interconnected with passageways 174 and 176,respectively. In this regard, the monitored pressures may be comparedwith a predetermined negative pressure value (e.g., corresponding with arisk of blood trauma or tissue damage or indicating that a suction wandis occluded against tissue), wherein automated stoppage of pump 32 or34, respectively, may be effected upon detection of a pressure that isbelow the predetermined negative pressure value and an alarm/indicatormay be otherwise provided at interface 50. A positive pressure mayindicate that a pump is operating in reverse wherein automated stoppageof pumps 32 and 34 may be effected upon detection of that positivepressure and an alarm indicator may be otherwise provided at userinterface 50. Further, the user may set at the user interface a highpressure limit and a low pressure limit and a desired control pointtherebetween. The monitored pressure is used as a feedback controlparameter to automatically adjust pump speed (32 or 34) to maintainpressure at the control point.

Tubing loops 178 and 180 interface with suction pumps 32 and 34 in thecomponent interface region 12 to provide for the desired suction. Thetubing loops 178 and 180 may be provided with clips 111 d and 111 e thatdefine the desired u-shaped configuration for the pump interface. Eachof such clips 111 d, 111 e, may be color-coded (e.g., yellow forsuction) and otherwise configured to facilitate loading of the tubingloops 178 and 180. The downstream ends of tubing loops 178 and 180 areinterconnected to integral passageways 182 and 184 of cartridge 120,which passageways 182, 184 are in turn each fluidly interconnected withthe integral passageway 185 for the passage of suctioned blood tosequestration reservoir 301.

Disposable assembly 100 may also include a third suction tubing line 186having a cannula assembly for interconnection with the left ventricle orvasculature of a patient's heart so as to provide for the venting ofblood or fluid that may accumulate therewithin. The third suction tubingline 186 may initially be plugged at the end to allow leak testing,occlusion testing of the suction pump 33, and testing to ensure that thepump loop 140 is loading in pump 33 in the correct direction. Tubingline 186 is interconnected to an internal passageway 188 of cartridge120 which in turn is interconnected to tubing loop 190. Pressure sensor44 is provided to monitor the pressure within the suction line 186 whichis interconnected with the passageway 188. Again, the monitored pressuremay be compared to predetermined negative and positive pressure values,as previously described with respect to suction lines 170 and 172,wherein automated stoppage of pump 33 may be effected upon detection ofa pressure that is below the predetermined negative pressure value orabove the positive pressure value and an alarm/indication may beprovided at interface 50 upon detection of an out-of-range condition(e.g., either above the positive pressure value or below the negativepressure value).

It should be noted that pressure sensors 40, 42 and 44 function in amanner similar to sensors 14 and 18 except that they measure bothnegative and positive pressure values. Tubing loop 190 interfaces withthe vent pump 33 provided in component interface region 12 to providethe desired suction in tubing line 186, as will be further described.Tubing loop 190 may be provided with a clip 111 f to define apredetermined u-shaped configuration for pump interface. The clip 111 fmay be color-coded (e.g., green) and otherwise configured to facilitateloading. The downstream end of tubing line 190 is interconnected to aninternal passageway 192 which, in turn, splits into two passageways 192a and 192 b. Flow through these passageways is controlled with valves402 and 403, respectively, to route the fluid either to thesequestration reservoir 301 or the filtered inlet of the venousreservoir 106, at the user's option.

The cartridge 120 in the embodiment illustrated in FIG. 3A comprises anintegral sequestration reservoir 301 for receiving fluids removed from apatient through first and second tubing suction lines 170 and 172,respectively, as well as through left ventricle tubing line 186. In thisregard, it can be seen that integral passageways 182, 184 and 192 arefluidly interconnected to the sequestration reservoir 301.

The inclusion of sequestration reservoir 301 in the embodiment of FIG.3A allows for selective, discretionary use of fluids collected therein.For example, such fluids may be processed to wash and separate red bloodcells and other desired components for later reinfusion. Moreparticularly, it can be seen that stopcock valve 303 may be provided oncartridge 120, in fluid connection with sequestration reservoir 301, toprovide for the selective flow of accumulated fluids from sequestrationreservoir 301 to a transfer bag (not shown) for subsequent autologousblood salvage procedures and return of the desired components to thepatient; or for flow directly to an autologous blood salvage system.

Alternatively, the embodiment illustrated in FIG. 3A allows for thereturn of fluids collected in sequestration reservoir 301 directly tovenous reservoir 106 via the inclusion of a valve assembly 401 incartridge interface region 20 that interfaces with an added integralpassageway 305 in cartridge 120. Valve 401 may be selectivelyopened/closed by a user or maybe automatically opened when thesequestration reservoir is full. When valve 401 is open, fluidscollected in sequestration reservoir 301 will flow through the integralpassageway 305 within cartridge 120, and then through tubing line 129 toa filtered inlet port at venous reservoir 106.

A vent 307 is provided at the top of sequestration reservoir 301 to ventgas that may accumulate in the reservoir 301. Additionally, thecartridge interface region 20 may be provided with one or more levelsensors for monitoring the fluid level within sequestration reservoir301. In this regard, a first level sensor 320 may be disposed adjacentto the top end of sequestration reservoir 301, wherein upon sensing offluid at a predetermined level within reservoir 301, control unit 10will operate so as to automatically open valve 401 so as to flow fluidfrom sequestration reservoir 301 to venous reservoir 106. The system maybe set up by the user so that, upon sensing fluid at the upper levelsensor, the control unit 10 may stop the suction and vent pumps andprovide an alarm so that the user can empty the sequestration reservoir.Alternatively, instead of stopping the vent pump 33, the control unit 10may automatically close valve 402 and open valve 403 to re-route thevent pump outlet from the sequestration reservoir to the venousreservoir. A second level sensor 322 may also be provided and disposeddownward from the first sensor, wherein upon the detection of fluid, analarm/indication may be provided at user interface 50. Alternatively,sequestration reservoir 301 may be provided with a continuous levelsensor such as that described in connection with FIG. 12. Alternatively,the level in the sequestration reservoir 301 could be sensedcontinuously by measuring the pressure at the bottom of the reservoirthrough the membrane with a pressure sensor.

Sequestration reservoir 301 includes a defoamer element 795 which may bevertically disposed to facilitate in the removal of gas from fluidaccumulating in venous reservoir 301. After cartridge 120 is loaded intoits mounting assembly 21, defoamer push bar 790 is advanced to aposition where it applies pressure through the vinyl backing ofcartridge 120 against the side of defoamer 795. This pressure ensuresthat there are no flow paths between defoamer 795 and the vinyl backingand that any fluid which enters sequestration reservoir 301 is caused toflow through the defoamer.

It should also be noted that, since in many potential applications, theblood collected through left ventricle tubing line 186 may be of a highquality nature, the embodiment illustrated in FIG. 3A comprises furtherfeatures that allow for the selective, direct flow of such blood fromthe cartridge 120 to venous reservoir 106. In particular, FIG. 3Aillustrates the inclusion of integral passageway spurs 192 a and 192 b,each of which interface with a corresponding valve assembly 402 and 403,respectively, provided in the cartridge interface region 20. In theevent that a user would like blood collected from the left ventricle tobe collected in sequestration reservoir 301, the user may selectivelycontrol valve 403 to be closed and valve 402 to be open whereupon thecollected blood will flow through integral passageway spur 192 a intointegral passageway 185 to sequestration reservoir 301. Alternatively, auser may selectively cause valve 402 to close and valve 403 to openwhereupon the collected blood will flow through integral passageway spur192 b, adjoining integral passageway 164, and out of cartridge 120through tubing line 129 to a filtered inlet port of venous reservoir106.

The component interface region may comprise a level sensing assembly 87positioned in immediate, predetermined relation to the region in whichvenous reservoir 106 is mounted. In this regard, the level sensingassembly 87 is operable to monitor the level of fluid within the venousreservoir 106 on an ongoing basis during procedures. Such monitoredfluid level may be presented both graphically and in volumetric measureterms at user interface 50. Additionally, the fluid level value may bemonitored in relation to predetermined minimum and maximum values,wherein automated slowage or stoppage of pump 31 may be effected whenthe fluid level drops below corresponding predetermined minimum valuesand wherein an alarm/indicator may be otherwise provided at userinterface 50 upon detection of an out-of-range condition.

One embodiment of such a level sensor is illustrated in function form inFIG. 12. In this embodiment, level sensor 87 operates on the theory oftime domain reflectometry which uses pulses of electromagnetic energy tomeasure distances or fluid levels. The level sensor 87 generates aninitial pulse 97 a. When the initial pulse reaches the surface of theblood in reservoir 106, part of the pulse is reflected. The level in thereservoir is determined by the measured differential of the reflectedpulse 97 c and the transmitted pulse 97 b in a manner known to those ofskill in the art. Level sensor 87 is mounted internally to the controlunit 10 in a location adjacent to the venous reservoir 106. The levelsensor 87 is oriented such that the level sensor is approximatelyparallel to the vertical wall of the venous reservoir and extends fromthe lower most portion to the upper most portion of the venousreservoir. In between the level sensor 87 and the venous reservoir 106is a thin wall, covering or coating that is thin enough and made of amaterial (e.g. plastic) permitting the transmission of signals into thevenous reservoir from the sensor as well as receiving reflected signalsfrom the venous reservoir, in particular reflections from the fluidlevel in the venous reservoir. The thin wall, covering, or coating wouldallow positioning the level sensor as close as possible to the externalwall of the venous reservoir to aid in signal transmission andreception. The wall could be a part of control unit 10. The level sensoris positioned approximately in a vertical plane such that thetransmitting and receiving portions of the sensor would cover the entireheight of the venous reservoir to ensure the venous reservoir levelcould be sensed from a full to empty condition. While a verticalorientation is described, an angled orientation would also functionallywork and may add resolution to the level signal.

As previously noted, user interface 50 includes a main display 54, usercontrol knob 52 and backup display 55. The main display 54 and backupdisplay 55 may be provided to display monitored parameters regarding oneor more of the fluid circuits discussed hereinabove, to provide alarmindications as noted hereinabove, and to establish predeterminedminimum/maximum or control values for monitoring and control purposes.Of particular note, the backup display 55 is located immediatelyadjacent to control knob 52, wherein when a given parameter is beingestablished via control knob 52, a user may readily observe the backupdisplay 55 as the knob 52 is being manipulated.

Another embodiment of the disposable assembly 100 and componentinterface of control unit 10 are schematically illustrated in FIG. 3B.As can be seen, the embodiment illustrated in FIG. 3B is similar in manyrespects to the embodiment illustrated in FIG. 3A. As such, componentshaving common functionality between the two embodiments are labeled withthe same reference number and the corresponding description of suchcomponents set forth above is applicable. Features unique to theembodiment illustrated in FIG. 3B are described below.

As shown in FIG. 3B, tubing line 116 includes a first spur 116 ainterconnected to an upstream side of an arterial filter 118, and asecond tubing spur 116 b interconnected to a downstream side of arterialfilter 118. Second tubing spur 116 b may be utilized forreplacement/bypass of arterial filter 118, while the first tubing spur116 a is utilized during oxygenated blood return to a patient duringcardiopulmonary bypass procedures. In particular, valve assembly 90 isprovided to receive tubing spur 116 a, and valve assembly 91 is providedto receive tubing spur 116 b, wherein valve assemblies 90, 91 may beselectively and/or automatically opened/closed together with other valveassemblies, to establish the desired fluid flow (e.g., through tubingspurs 116 b during filter replacement, and through tubing spur 116 aduring bypass procedures).

Valve assembly 93 is provided to receive tubing line 125 and may beselectively and automatically opened/closed, including, for example,selectively opened for retrograde cerebral perfusion or to quicklyreprime the venous tubing line 104 after initial bypass procedure endsin the event the patient needs to go back on bypass.

During bypass procedure control unit 10 may operate to close tubing line122 and direct blood flow from arterial filter 118 through purge line119 when bubbles are detected by sensor 114. Further, in the embodimentof FIG. 3B, control unit 10 may operate to close tubing line 122 byclosing arterial line valve 92 when gaseous bubbles are detected bysensor 114 and/or sensor 126 thereby causing blood to flow back to thereservoir 106 via tubing line 125. For such purposes, tubing line 125 isinterconnected to the venous entry module 108 of the venous circuit asdescribed hereinabove.

During cardioplegia delivery (e.g., when pump 35 is operating and valve96 is open) and/or during hemoconcentration procedures (e.g., when pumps37 and 38 are operating to circulate blood through a tubinghemoconcentration assembly 134), the monitored pressure may be comparedwith a corresponding predetermined minimum value to insure an adequatefluid pressure at cartridge 120 (e.g., so as to reduce any risk ofcavitation or air transfer across the membrane of oxygenator 112). Inthe event the monitored pressure is below the desired level, automatedstoppage of pump 35 (e.g., in the case of cardioplegia delivery) andautomated stoppage of pumps 37 and 38 and closure of valve 96 (e.g., inthe case of hemoconcentration procedures) may be effected and analarm/indication may be provided at interface 50.

Integral passageway 130 is fluidly interconnected to a tubing loop 132,and may also be fluidly interconnected to a tubing/hemoconcentratorassembly 134. In the later regard, tubing/hemoconcentrator assembly 134may be optionally interconnected to the disposable assembly 100 when useof a hemoconcentrator 134 a and waste bag 134 b is desired.

Pressure sensor 86 may also be provided to sense the pressure within thetubing/hemoconcentrator assembly 134 in the event that ahemoconcentrator is employed. In this regard, the monitored pressure maybe compared with a predetermined minimum pressure value necessary toinsure flow through the membrane of hemoconcentrator 134 a, wherein ifthe pressure falls below the minimum an alarm or other indication may beprovided at user interface 50. Further, the monitored pressure inassembly 134 may be compared with a predetermined maximum pressurevalue. A monitored pressure that exceeds the maximum value may indicatethat the outlet of hemoconcentrator 134 a has become occluded, whereinautomated stoppage of pump 37 and pump 38 may be effected and an alarmor other indication may be provided at user interface 50.

In the embodiment of FIG. 3B the downstream end of tubing loop 140 isinterconnected with integral passageway 142 having a filter 144interposed therewithin. Filter 144 serves to filter particulates greaterthan a predetermined size (e.g., greater than 0.2 microns via a filterscreen). Filter 144 may also comprise at least one vent (not shown)having a hydrophobic membrane for venting air bubbles. In this regard,filter 144 may include two hydrophobic vents (not shown), one on eachside of a vertical filter screen, for venting air bubbles from a primingsolution during priming and for venting air bubbles from solutionspassing therethrough (e.g., cardioplegic crystalloid solution duringcardioplegia delivery).

Pressure sensor 16 is provided in cartridge interface region 20 forsensing the fluid pressure within integral passageway 142. The monitoredpressure may be compared with a predetermined value during cardioplegiadelivery (e.g., when pump 36 is operating and valve 96 and one of thevalves 99 are open). If the monitored pressure exceeds the predeterminedvalue (e.g., indicating the filter 144 is clogged), then analarm/indication can be provided at interface 50, and the filter 144 maybe automatically or manually bypassed (e.g., via operation of valve 93so as to open bypass line 143).

For purposes of priming and for filtering in conjunction with priming,valve assemblies 94 and 95, respectively, are provided to receive tubinglines 119 and 166, respectively, for selective and automaticclosure/opening.

With further regard to the delivery of the crystalloid solution, valveassembly 93 is provided to receive crystalloid bypass tubing line 143for selective and automatic opening/closure thereof, including forexample opening upon clogging of crystalloid filter 144, as detected bypressure sensor 16. That is, in the event sensor 16 detects a pressuregreater than a predetermined value, valve assembly 93 can beautomatically and/or selectively opened wherein crystalloid solutionwill flow through bypass tubing line 143 and back into integralpassageway 146.

The downstream ends of tubing loops 178 and 180 are interconnected tointegral passageways 182 and 184 of cartridge 120, which passageways182, 184 are in turn each fluidly interconnected with the integralpassageway 164 for the passage of suctioned blood out of cartridge 120and through tubing line 129 to the filtered inlet of venous reservoir106 for reuse.

Further, passageway 164 may be interconnected to an outlet (not shown)that may be selectively utilized for passing suctioned blood into aseparate reservoir (not shown).

Finally, disposable assembly 100 may also include a transfer bag/tubingassembly 194 (not shown in FIGS. 2A and 2B) that may be utilized forreceiving blood from passageway 130 of cartridge 120. The transferbag/tubing assembly 194 may be employed, for example, to remove excessfluid from the circuit during bypass procedures, to retrieve blood fromthe circuit post bypass for later reinfusion to the patient or forcell-saving procedures.

Pressure sensor 14 may also be used as a means of checking for properarterial cannula placement before going on bypass. When arterial patientvalve 92 is open during test connection mode as described hereafter, thepatient pressure at the cannula can be read at sensor 14.

While FIGS. 3A and 3B correspond with embodiments implementing variousaspects of the present invention, other potential embodiments whichincorporate one or more of the inventive features of the presentinvention would be apparent to those skilled in the art.

V. Disposable Cartridge

As illustrated in FIGS. 13-24, the perfusion cartridge 120 can be madeof a variety of materials including polymeric materials, metals andcomposite materials. In a preferred embodiment, the perfusion cartridge120 of the present invention is formed from polymeric materials whichare thermoformed medical grade plastics. Cartridge 120 has a pluralityof fluid passageways integrally defined therewithin. By way of example,cartridge 120 may be constructed from a clear, molded front piece (e.g.,molded plastic which defines all but a back side of each integralpassageway), and an interconnected, pliable back layer (e.g., a vinylsheet that defines a back side of each integral passageway) attachedthereto. In addition to the integral passageways, cartridge 120 mayinclude one or more passive components. Such components may include oneor more filters and bubble traps. Various conduits may be formed intothe perfusion cartridge 120 during manufacturing such that each of thetop and bottom plates or pieces partially define portions of theconduits. Typically, the front portion 802 is translucent to allow forvisual inspection of each of the conduits that flow through thecartridge 120. In addition, the integrated fluid conduits are located atvarious depths and can pass above or below each other.

FIGS. 13-24 are various views of cartridge 120. FIG. 13 is a frontperspective view. FIG. 14 is a front plan view. FIGS. 15 and 16 areright and left side views, respectively. FIGS. 17 and 18 are top andbottom views, respectively. FIG. 19A is a back plan view and FIG. 19B isa back perspective view. FIG. 20A is a cross-sectional view along lineA-A of FIG. 19A. FIG. 20B is a detail view of a portion of FIG. 20A.FIG. 21 is a cross-sectional view taken along lines B-B of FIG. 19A.FIG. 22 is a back plan view with the flexible back layer removed tobetter show the various fluid channels and related components withincartridge 120. FIGS. 23A, 23B, 24A, and 24B are partial views of a valvestation located in cartridge 120.

In each of these figures, components that have been previously describedretain the same reference numerals. This includes the various internalpassageways or fluid conduits formed by the cartridge. The various inletand outlet ports of the cartridge have been labeled with the referencenumeral of the external tubing line connected at the port. Thoseportions of the cartridge which interface with pressure or temperaturesensors or with valves comprise sensor or valve stations and are labeledindividually with the reference numeral of the sensor or valve withwhich they interface followed by a small “a”. Thus, for example, thesensor station interfacing with cardioplegia line pressure sensor 18 isreferenced as 18 a. Features of cartridge 120 not previously describedare discussed below.

Cartridge 120 includes a front substantially rigid portion 802. Frontportion 802 defines substantially all of the structure of the variouscomponents and passageways of the cartridge. For example, front portion802 defines the shape and contour of sequestration reservoir 301 exceptfor the back portion thereof. A flexible back layer 804 is connected tothe back side of front portion 802. Any flexible, durable, fluidimpermeable material which is suitable for contact with a patient'sblood may be used. A suitable material is a sheet of vinyl. The sheetcan be attached to the front portion by use of medical adhesives orwelding techniques known to those of skill in the art. The back layermay be comprised of a flat sheet or, alternatively, can be formed into acontoured shape. Formed elements in the vinyl can assume various formedshapes and can include pressure diaphragms as shown in FIGS. 19A and19B, valve diaphragms as shown in FIGS. 23A, 24A, 23B, and 24B, fluidpassageways matching those on the cartridge as shown in FIGS. 19B and20B, sequestration reservoir 301 and sequestration reservoir defoamer790 as shown in FIGS. 15 to 21. The pressure diaphragms isolate thepressure sensor from the cartridge to provide more accurate pressurereadings. The valve diaphragms help lower the resistance to valveopening and closing, and can provide a transition zone in the fluidflowing from the passageway through the valve. Fluid passageways can beshaped to smooth fluid flow and/or provide a more consistent crosssectional fluid volume through passageways particularly where enteringor exiting other features such as ports, pressure sensing regions orvalve regions. The sequestration reservoir volume may be increasedand/or flow enhanced through vinyl forming. In particular, by forming apocket in the vinyl, the defoamer may be placed into the pocket as bestseen in FIG. 20A. A pocket also helps form a sealing interface whenpositioned against defoamer push bar 790 located in the cartridgeinterface region 20. Vinyl forming may be accomplished by formingtechniques known to those skilled in the art.

As seen in FIGS. 20A and 21, the sequestration reservoir includes adefoamer support element 806. Support element 806 comprises a pluralityof struts 806 a and 806 b which are spaced apart on either side ofdefoamer 790 and which support defoamer 790 in the sequestrationreservoir 301.

As shown in FIGS. 23A, 23B, 24A, and 24B, the valve stations include avalve chamber 808 in the cartridge 120. The valve chamber 808 includesat least first 810 and second 812 passageways. A flexible member 804 ispositioned over the valve chamber 808 above first 810 and second 812passageways.

Typically, first passageway 810 contains a raised lip portion 816 whichextends toward flexible back layer 804. A portion of backlayer 804adjacent raised lip portion 816 is formed as a flexible pleated member814. A plunger 818 provided in the structural interface is located overthe valve chamber 808. To close the valve, plunger 818 is caused toimpact and deflect the flexible member 814 to contact the raised lipportion 816 of the first passageway 810. This deflection and contactprevents fluid from flowing out of or into the first conduit 810. Toopen the valve, the plunger 818 is retracted from the raised lip portion816 such that fluid pressure displaces the flexible member 814 from theraised lip portion 816 of the fluid conduit 810.

In a further embodiment of the present invention, the cartridge 120includes a first integral passageway path which occurs in a first plane.The first integral passageway has an entry port and an exit port fromthe cartridge 120. The first integral passageway, thus, defines firstand second areas in cartridge 120, both lying in the first plane andbeing separated by the first integral passageway. Cartridge 120 alsoincludes a second integral passageway which has an entry port and anexit port from the cartridge. The entry port of the second integralpassageway occurs in the first area of the first plane, and the exitport of the second integral passageway occurs in the second area of thefirst plane. Thus, the first and second conduit paths crossover at apoint. At the point of cross-over of the first and second integralpassageways, the second integral passageway occurs in a second plane.

In the present invention, as shown in FIGS. 13-24, the perfusioncartridge 120 can be interconnected with a number of fluid circuits. Thefluid circuits include a cardiopulmonary circuit which include thevenous and arterial circuits, a cardioplegia circuit, a cardiotomy orsuction/vent circuit and a fluid management or priming circuit all aspreviously discussed. The cardiopulmonary circuit is designed tofunctionally replace and/or supplement the heart and lungs during heartsurgery. The cardioplegia circuit delivers cardioplegia to the heart todiscontinue beating in a manner that will facilitate operativeprocedures and minimize damage to the myocardium. The cardiotomy circuitis used to withdraw or suction blood and other fluids from the openheart or chest cavity and deliver it to the cardiopulmonary circuit. Thefluid management circuit is used to provide priming fluid, i.e., blood,to the disposable assembly 100 and maintain a proper flow of fluid inthe other circuits. In another embodiment, two cartridge assemblies maybe interconnected. For example, a first cartridge assembly including thecardioplegia circuit may be connected to a second cartridge assemblyincluding a cardiopulmonary circuit, a cardiotomy circuit and a fluidmanagement circuit can be interconnected.

In the embodiment described herein the cardiopulmonary (arterial andvenous) circuit is not interconnected with the disposable cartridge 120except for air purge and fluid sampling functions. However, it should beappreciated that the cardiopulmonary (arterial and venous) circuit couldbe included within the cartridge 120.

VI. System Architecture.

Control unit 10 includes a plurality of processors which together withsystem user interface 50, pump user interfaces 31 b-36 b and pumpcontrol knobs 31 a-36 a operate to control various components of thecontrol unit 10 according to preprogrammed and/or user establishedinstruction sets and user input. In this regard, and referring now tothe block diagram of FIG. 25, a control unit 10 comprising processors300, 306, 304 and 312 is illustrated. Processor 300 is provided tointerface with the main display 54 of the user interface 50, and may bea personal computer provided with graphics to facilitate operation ofthe main display 54. Monitor/control processors 306 are separatelyprovided for automated monitoring and control, respectively, of thevarious components comprising control unit 10. Backup display 55 mayalso be provided with redundant monitoring/control processors 304,separate from processors 300 and 306. It is also noted that valves,sensors, flow control components, temperature control components, gascircuit components or other components comprising component interfaceregion 12 may also be separately provided with separate monitoring andcontrol processing chips. Each pump 31-36 also has its ownmonitor/control processor pairs 312. All of the above-mentionedprocessors are interconnected through a communications network.

Processors 300, 306, 304, and 312 are interconnected to receivemonitoring signals from the various pressure, bubble, temperature,oxygen saturation, hematocrit, level, flow, and other sensors 314 thatcomprise the control unit 10, and that interface with the disposableassembly 100. In this regard, the monitored signals provide anindication of measured values which may be processed at one or more ofthe processors in relation to one or more predetermined maximum/minimumvalues so that one or more of the processors may issue control signalsto flow control components 380, temperature control systems 330 or gascircuit components 340 based on preprogrammed instruction sets and/orother indication signals to system user interface 50 and/or pump userinterface 31 b-36 b to prompt a user regarding a monitored condition ofpotential concern. As will be described, system user interface 50 allowsa user to input or modify one or more of the processors parametersettings which one or more of the processors rely upon in issuinginstruction signals to flow control components 380, temperature controlsystems 330 and/or gas circuit components 340 and indication/alarmsignals to system user interface 50.

As indicated in FIG. 25, the flow components 380 comprising the controlunit 10 include the various pumps and valve assemblies describedhereinabove, as well as the venous line clamp 46. Based on signalsreceived from the various pumps or pressure sensors, the processors maybe preprogrammed to automatically calculate flow rates in the variousfluid circuit lines for monitoring and display at user interface 50. Thetemperature control systems 330 include controls for establishing thetemperature and flow of heating/cooling fluid through the cardioplegiaheat exchanger 148 and for controlling the temperature and flow of theheating/cooling fluid circulated through a heat exchanger interconnectedto or integrally provided with oxygenator 112. Other features andfunctions of the system architecture are described in other sectionsherein.

1. Gas Circuit

Referring now to FIG. 26, a schematic block diagram for the gas circuit340 referenced in FIG. 25 will be briefly described. The gas circuit 340may comprise a plurality of external gas sources for air (342 a), for O₂(342 b) and for an O₂/CO₂ mixture (342 c), having corresponding in-linefilters 344 a, 344 b and 344 c, and pressure regulators 346 a, 346 b,and 346 c, for flowing the respective gases via corresponding checkvalves 348 a, 348 b, and 348 c into a valve manifold 350. Valve manifold350 includes valves 352 a, 352 b and 352 c set to establish the desiredflow/relative percentage of each gas type. Flow meters 354 b and 354 cmay be provided upstream (as shown) or downstream of valve manifold 350for the O₂/CO₂ source line and O₂ source line and/or air source line. Asillustrated, the three gas source lines may flow into a common linedownstream of the manifold 350. The common line then passes through atotal flow meter 356. From flow meter 356 the single stream may bepassed through a vaporizer 358 outside of control unit 10 forintroduction of an anesthetic agent. A pressure sensor 360 may beprovided to monitor the fluid pressure at filter 362. In the event thepressure exceeds a predetermined maximum value (e.g., indicating thatfilter 362 is clogged), an alarm or other indicator may be provided atuser interface 50. Additionally, to insure the desired pressure atoxygenator 112, an additional pressure sensor 364 may be utilizeddownstream of the filter 362 and upstream of the oxygenator 112. In theevent the pressure exceeds a predetermined maximum value, valves 352 a,352 b, and 352 c may be closed partially or fully to prevent gas bubblesfrom crossing the oxygenator membrane into the blood. The gas fromfilter 362 then flows into the oxygenator 112 via inlet port 518 aprovided in the control unit 10 through the oxygenator 112, and into thecontrol unit 10 via the outlet port 518 b (on FIG. 8B). At that point,the gas flow stream will comprise the oxygen-depleted, CO₂-containingexhaust from oxygenator 112. Such exhaust may then be passed through aliquid leak detector 366 for monitoring purposes (e.g., to detect anyleakage through the oxygenator membrane of blood or priming fluid), andinto a scavenge line. An optional gas concentration monitoring systemmay be included having sampling pumps 368 a and 368 b to draw gassamples downstream and upstream, respectively, of oxygenator 112. Thegas samples may be passed through a dryer 369, analyzed by monitor 370,and returned to the scavenge line. The flow meters 354 b, 354 c, 356,and monitor 370 may be interconnected to user interface 50 to provideinformation for display and monitoring for alarm indications. Theinformation provided by the flow meters and concentration sensors,combined with the known blood flow rate, venous saturation, hematocritand temperature, can be used to estimate arterial blood gasconcentrations (e.g., pO₂ and PCO₂). The gas concentrations measured bythe monitor 370 can be compared to the concentrations calculated fromthe flow rates measured by flow meters 354 b, 354 c, and 356. If thedifference between measured and calculated concentration exceeds apredetermined maximum value, an alarm/indicator may be provided at userinterface 50. The arrangement of flow meters and valves allows acomparison of flow meter measurements to verify correct operation ofindividual flow meters. For example, valves 352 c and 352 a could beclosed, allowing flow only from the O₂ source through flow meters 354 band 356. The measured flow rates from meters 354 b and 356 should beequal if the flow meters are operating properly. Similar checks/testscould be performed with respect to verifying gas source composition andconnection.

VII. System User Interface.

The system user interface 50 includes a control knob 52 and userdisplays 54 and 55 that provide for the automatic redundant display ofalarm indications and certain monitored parameters, and provide forselective user control of various system components. Both main display54 and backup display 55 may provide a functional user interface (e.g.,via touch screen capabilities). Important subsets of the variousfeatures described below with respect to main display 54 may also beprovided at backup display 55, either all the time or if failure of maindisplay 54 is detected by the system or by the user. In addition to itsbackup display functions, display 55 serves primarily as a numeric dataentry screen, as described below.

Numeric data entry is accomplished by using the control knob 52 and bothuser displays 54 and 55, as follows. The user contacts a touch screenbutton on either display 54 or 55 to initiate modification of aparticular numeric value represented by that button. The value beingmodified then appears (usually in a large font) on display 55, as wellas appearing within the button originally contacted on display 54 (orits analog on 54, if the original button was on display 55). At thispoint, the knob 52 may be turned to affect changes in the valuedisplayed in both places. This dual display concept is to provideredundant display of important data parameters as are they are beingadjusted, thereby giving an important safety cross-check againstincorrect data entry. In most cases, as the number is being adjusted onthe screens, it is also taking immediate effect in the system (on-lineadjustment). For example, turning the knob to adjust venous line clampposition causes the clamp to move immediately to the value entered. Dataentry is terminated by pressing the knob 52 in, or by touching theoriginal touch button or anywhere else on the touch screen. Because ofthe on-line nature of such adjustments, terminating the data entry isnot in anyway “confirming” or “setting” the value entered; that hasalready happened. Terminating the data entry simply exits the adjustmentmode for that particular value. There are many examples of specific dataentry actions throughout this section.

FIGS. 27-33 illustrate examples of one embodiment of the system userinterface 50, and are presented for illustrative purposes. Thearrangement, controls, and information presented on the user interfaceare not limited to that shown here.

As shown in FIG. 27, processor-driven display 54 is controlled to definethree display regions for information presentation and user control. Thescreen of display 54 comprises a first region 200, a second region 220,and a third region 240. The first region 200 provides for automaticalarm status messages and corresponding user control buttons that arepresented when monitored system parameters exceed/fall belowpredetermined established values (e.g., factory set values or userestablished values). The second region 220 and third region 240 will bedescribed further hereinbelow.

Alarms:

The first region 200 of display 54 provides alarm and status messagesthat are presented when certain monitored system parameters exceed/fallbelow selectable, predetermined established values and/or an otherwiseundesired condition is detected. FIGS. 28A-28F illustrate a variety ofsuch messages. In this regard, it should be noted that the messages arepresented in relation to their relative degree of importance. That is,in the illustrated embodiment, messages which are of predetermined“critical” nature are displayed against a red box background whilemessages of a predetermined “warning” nature are displayed against ayellow box background. Further, it should be generally noted that when acondition is detected that would trigger a “critical” message suchmessage will be presented together with a touch screen button that maybe immediately contacted by a user to override the alarm. That is,detection of a “critical” condition may result in automatic stoppage ofa given system component (e.g., pump 31 or pumps 35 and 36), in whichcase, the “critical” message may be presented with a touch screen buttonthat may be contacted to restart the stopped component. Alternatively,detection of a “critical” condition may result in display of a button(e.g., with the “critical message”) that may be contacted by a user toeffect an immediate stoppage of a predetermined component displayed withthe message (turn off the override). Additionally, it should be notedthat with respect to the “critical” messages, a predetermined hierarchyis preferably established wherein the order of presentation of such“critical” messages will be determined in relation to the hierarchy aspreprogrammed at the embedded processor.

The following are examples of “critical” conditions that may trigger anautomatic response and a “critical” alarm message. Many other criticalalarms may exist in the system:

-   -   1. Detection of an air bubble in tubing line 122 or tubing line        156. Such a detected condition may automatically trigger        stoppage of pump 31 and/or pumps 35 and 36. Selective, user        response buttons may be provided with the corresponding        “critical” messages to provide a user with the touch screen        capability to restart the stopped pump.    -   2. Detection of a pressure in line 122 or of a pressure in line        156 that exceeds a corresponding predetermined maximum value.        Detection of this condition may trigger an automatic stoppage of        pump 31 and/or pumps 35 and 36. Alternatively, the pump may slow        until the desired range is re-achieved. Again, button displays        may be provided for selective, user restart of the affected        pumps.    -   3. Detection of a volume level in venous reservoir 106 that        exceeds or falls below a predetermined level.

Various detected conditions are reflected by FIGS. 28A-28F.

Referring specifically to FIG. 28A, a “critical” alarm box 202 a′ ispresented with the message: “LOW LEVEL-Pump Stopped”

This message indicates that the volume in reservoir 106 has beendetected to have fallen below a predetermined alarm value. The messagealso indicates that pump 31 has been automatically stopped. It shouldalso be noted that the message box 202 a′ provides a touch screen buttonentitled “Restart Pump” 202 a″. Button 202 a″ allows a user toimmediately take responsive action, i.e., to contact the “Restart Pump”button 202 a″ so as to start arterial pump 31, by overriding the alarm.

At this point, it should also be noted that in the event of a “critical”message (e.g., the message is displayed against a red background), thecontrol unit 10 may provide for a first audible alarm to a user.Further, in the event of a non-critical message (e.g., a “warning”message displayed against a yellow background), control unit 10 mayprovide a second audible alarm that is different than the first.Correspondingly, the first region 200 of display 54 may be provided witha touch screen “Mute” button 204 which allows a user to selectivelydisable the most recent audible alarm. That is, audible alarms may besuccessively and separately “muted” in relation to each successivetriggering-alarm event. The “Mute” button 204 only appears when there isone or more audible alarms currently sounding, and it disappears afterbeing pressed (thereby stopping the audible signal) until the nexttriggering event occurs causing a new alarm and audible to occur. Thus,the “Mute” button only appears when needed.

FIG. 28B illustrates an alarm box 202 b′ with the message: “LOWLEVEL-Pump On”.

This message indicates that the volume in reservoir 106 has beendetected to have fallen below a predetermined value and that pump 31 ison (because the alarm is overridden). Block 202 b′ also provides a touchscreen button entitled “Stop Pump” 202 b″ to allow a user to immediatelystop arterial pump 31 upon contact with button 202 b″.

In FIG. 28C an alarm box 202 c′ is presented with the message: “LEVELOK—Pump Stop Disabled”.

This message indicates that the volume in reservoir 106 is within anacceptable range but that the automatic pump stoppage feature of controlunit 10 has been overridden (e.g., the user has contacted the button 202a″ shown in FIG. 28A). To reactivate the automated pump control feature(turn off the override), a user may contact button 202 c″.

FIG. 28D illustrates a plurality of “critical” alarm boxes correspondingto response buttons 203 a″, 203 b″, and 203 c″ each of which would beillustrated against a red background, and a single “warning” alarm box206 a′ which would be presented against a yellow background. FIG. 28Eillustrates a plurality of “critical” alarm boxes and a plurality“warning” alarm boxes. The presence of the “MORE button 208 a indicatesthat there are more alarms than can be displayed within region 200,which can be selectively cascaded into the second display region 220 viacontact with the “MORE” button 208 a, as shown in FIG. 28F. Pressing the“LESS” button 208 b in FIG. 28F will collapse the alarms back withinregion 200, as shown in FIG. 28E.

Dedicated Area:

The second region 220 presents selected, predetermined importantinformation sets to monitor bypass parameters, including valuescorresponding with selected fluid flow parameters monitored by variouscomponents of control unit 10, as well as other parameters monitored byexternal systems. More particularly, in the screen display embodimentillustrated in FIG. 29, five different information sets are presented infive corresponding sub-regions 222, 224, 226, 228 and 230, having thesub-region headings of “Venous”, “Arterial”, “Cardioplegia”, “Blender”and “Other”, respectively. The alphanumeric information in the differentsub-regions may be color coded for ready observation (e.g., thealphanumeric information may be blue in “Venous” sub-region 222, red in“Arterial” sub-region 224, yellow in “Cardioplegia” sub-region 226 andwhite in “Blender” and “Other” sub-regions 228 and 230, respectively).

The information displayed in sub-region 222 under the “Venous” headingpertains to parameters of the venous blood flowing from a patient intovenous reservoir 106 of disposable assembly 100 during a bypassprocedure. More particularly, the monitored venous blood values includea measure of the venous blood oxygen saturation (i.e., “SAT”), venousblood hematocrit (i.e., “HCT”) and venous blood temperature (i.e.,“Temp”). Such values are monitored by corresponding oxygen saturationhematocrit and temperature sensors 85 and 81, respectively, in thecomponent interface region 12. Of note, information regarding thevolumetric content of venous reservoir 106 is provided both in ananimated manner and numerically by the graphic reservoir in sub-region222. That is, as the level of fluid raises and lowers in venousreservoir 106 during a bypass procedure, a corresponding animated fluidlevel (e.g., illustrated in red) will be presented in the graphic venousreservoir shown in sub-region 222. Additionally, a numericrepresentation of the volumetric level within venous reservoir 106 willbe increased/decreased. The volumetric level of fluid within reservoir106 is determined via the level sensor 87 located in component interfaceregion 12.

The “Venous” sub-region 222 further includes object buttons 222 a, 222 band 222 c having touch screen capabilities to allow a user toselectively control venous line clamp 46 of the component interfaceregion 12 on control unit 10. In particular, the “Full Open” and “FullClose” buttons 222 a and 222 c, respectively, allow a user toselectively, fully open and fully close venous line clamp 46 upon screencontact. Object button 222 b allows a user to select a desired percentof fluid passage through venous tubing line 104 at venous line clamp 46.That is, pursuant to contact with button 222 b, a user may then utilizethe control knob 52 on system user interface 50 to set a desiredpercentage for fluid passage through tubing line 104 at venous lineclamp 46. The desired percentage is established by dialing/rotating knob52 until the desired value is displayed by main display 54 and back updisplay 55. The VLC is moved immediately to the desired position as theknob is moved. A user may then either push the knob 52 or contact button222 b or any other touch screen portion of display 54 to exit theadjustment mode. For example, if venous line clamp 46 is in an openposition and a user desires to reduce the flow of venous blood flow intovenous reservoir 106 (e.g., due to a detected high level of fluid withinvenous reservoir 106), a user could contact button 222 b and “close”venous line clamp 46 a desired amount via rotation of control knob 52.The set flow percentage will be presented in an illuminated mannerwithin the center of object button 222 b and on the back up display 55.The percentage is displayed as a percent of flow expected if the venousline clamp was fully (100%) open.

The information presented within sub-region 224 under the heading“Arterial” pertains to ongoing monitored parameters of the blood passingfrom venous reservoir 106 through oxygenator 112 for return to apatient. More particularly, the monitored parameters include thepressure of the oxygenated blood in line 122 (i.e., “Pressure”), theflow rate of the blood at pump 31 (i.e., “Flow”) and the temperature ofthe blood in line 122 (i.e., “Temp.”). The pressure and temperaturevalues are monitored on an ongoing basis by the pressure sensor 14 andtemperature sensor 88 provided in component interface region 12 ofcontrol unit 10. The flow rate may be automatically determined bymonitoring the RPMs of arterial pump 31 at the pump processor 312 and byusing the monitored RPM values with stored stroke volume-valuescorresponding with pump 31 to calculate flow rate, or to display theflow rate from a flow meter. Such flow rate may be automaticallyadjusted to compensate for any blood flow downstream of pump 31 that isnot directed through arterial tubing line 122. Arterial blood flow maybe adjusted to compensate for the flow diverted to the cardioplegiacircuit (or other circuits). This is done by monitoring the flow throughcardioplegia blood pump 35, and adding that much flow to arterial pump31 so that the flow to the patient remains the same. Assuming a flowmeter is not available, the flow displayed in sub-region 224 will bethis calculated patient line flow.

The information set provided under the “Cardioplegia” heading withinsub-region 226 includes information corresponding with monitored andpreset values corresponding with the cardioplegia mixture flowed throughcardioplegia tubing line 156 to a patient. Such parameters include thepressure of the cardioplegia mixture (i.e., “Pressure”), the flow rateof the cardioplegia mixture (i.e., “Flow”) and the temperature of thecardioplegia mixture (i.e., “Temp.”). Such information is obtained viamonitoring signals received from pressure sensor 18, pumps 35 and 36 andtemperature sensor 153. Again, the signals from pumps 35 and 36 reflectRPMs which can be employed with stroke volume-related values for pumps35 and 36 to determine cardioplegia flow rate, or the flow rate from aflow meter may be displayed. Sub-region 226 also provides for thedisplay of information relating to a patient's coronary sinus pressure(i.e., “Coronary Sinus”). Such pressure may be obtained from anauxiliary sensor connected to unit 10 or from a conventional operatingroom patient monitor interconnected to unit 10. Additionally, sub-region226 displays values showing a target amount of cardioplegia mixture tobe delivered in a given increment (i.e., “Bolus”), the total amount ofcardioplegia delivered throughout the case (i.e., “Total”), and theamount of time that has passed between cardioplegia delivery periods(i.e., “Ischemic Time”). The “Ischemic Time” is automatically determinedby timing the interval between when pump 35 or 36, or both pumps 35 and36, stop and subsequently restart.

In the sub-region 228 corresponding with the “Blender” heading,monitored and preset values are presented which pertain to the flow ofgas to the oxygenator 112. In particular, in the gas circuit of FIG. 26,the flow rate of the gas supplied to the oxygenator 112 is monitored byflow meter 356. Such amount may be displayed in sub-region 228 (i.e.,“Flow”). Further, the desired, preset oxygen percentage for the inspiredoxygen supplied to oxygenator 112 is displayed (i.e., “FiO₂”), and thedesired preset CO₂ percentage of the inspired carbon dioxide supplied tooxygenator 112 is displayed (i.e., “FiCO₂”). Such percentages may bedisplayed via signals provided to one or more of the processors of unit10 from valves 352 a-352 c in the gas circuit shown in FIG. 26.

The “Other” sub-region 230 is provided to display other monitored valuesand is re-configurable by a user. In FIG. 29, the “Other” sub-region hasbeen configured to display values corresponding with a patient'sarterial blood pressure (i.e., “Patient Arterial”) and temperature(“Patient Temp.”). Such values may be monitored via an external system(e.g., an operating room monitor) which is interconnected to theembedded processor in control unit 10. Further, the monitored percentageof CO₂ in the expired oxygen passing out of oxygenator 112 may bedisplayed (i.e., “FeCO₂”). Such percentage may be provided by monitor320 in the gas circuit shown in FIG. 26.

Tabbed Area:

The third region 240 of display 54 provides for the selective display ofvarious context-driven, information sets and correspondingcontext-driven user-control options. During a bypass procedure, suchinformation sets and control options may be navigated via selectivecontact with a plurality of context-driven touch screen tabs, as will befurther described.

Referring to FIG. 30A, when initiating a procedure, a first tab 242 willpresent a title that changes in corresponding relation to predetermined,pre-bypass steps to be completed. When these steps are completed asdescribed below, the first tab 242 will present the title “Main” untilbypass and post-bypass are complete, when it will present the title“Unload”. In addition to tab 242, a plurality of other tabs may beselectively employed to access different screen sets. As will be furtherdescribed, tabs 244, 246, 248, 250, 252, and 254 are available forselection and use at any time during setup or during bypass proceduresand will illuminate upon selection.

“A-V”: Tab 244 may be employed to display a pictorial and/oralphanumeric representation of and selectively control certain controlunit 10 functions relating to the venous and arterial circuits,collectively, arterial-venous circuit. Additionally, touch key buttonsare displayed for immediate user control of selected other functions.

“CPG”: Tab 246 may be employed to a display pictorial and/oralphanumeric representation of and selectively control certain controlunit 10 functions relating to the cardioplegia circuit, e.g., includingsettings such as cardioplegia ratios or bolus values. Additionally,touch key buttons are displayed for immediate user control of selectedother functions.

“Suction/Fluids”: Tab 248 may be employed to display pictorial and/oralphanumeric representations of and selectively control certain controlunit 10 functions relating to the suction and left ventricular circuits.Additionally, touch key areas are displayed for immediate user controlof selected other functions, including the addition of fluids throughthe prime lines.

“Gases”: Tab 250 may be employed to display pictorial and/oralphanumeric representations of and selectively control certain controlunit 10 functions relating to the gas circuit. By way of example, tab250 may be employed to establish the gas sweep rate and/or defined FiO₂flow for oxygenator 112. Additionally, gas combination ratios, relativeconcentration values and mass flow rate relative to fluid flow rate maybe established for gas circuit 340. For example, the user may establisha desired mixture of O₂/CO₂, and air to be established at valves 352 c,352 b, and 352 a. Additionally, tab 250 may be employed to presentvarious monitored gas pressure readings, including readings taken bypressure sensors 360 and 364 comprising gas circuit 340.

“Waveforms”: Tab 252 may be employed to display graphical waveforms andtrend settings, and alphanumeric representations, including waveformscorresponding with patient pressure, temperature and ECG signalsreceived by the embedded processor from external or internal systems.

“Settings”: Tab 254 may be employed to display a pictorial and/oralphanumeric representation of and selectively control certain controlunit 10 functions relating to the various system parameter settings.Additionally, touch key buttons are displayed for immediate user controlof other parameter settings.

Main Tab: Tab 242 in region 240 is used to guide the operator through asequence of steps to setup, load, and prime the tubing set, run thebypass procedure, run post-bypass steps, and, finally, unload the tubingset. In this regard, the title of tab 242 changes to “User Setup”,“Load”, “Auto-Prime”, “Main”, and “Unload” as the major steps of theprocedure are executed, and where “Main” covers both bypass andpost-bypass operations.

Many of the operations encompassed by the Main tab are sequential innature, meaning that one step must be completed before the next step(s)can be accomplished. Therefore, the screens in tab 242 enforce thissequential nature by both the instructions presented in message block245, and by not “enabling” touch screen buttons corresponding to latersteps until the required prerequisite steps are completed. A button thatis not enabled does nothing when touched, and also has a “dimmed out”look, where the text on the button is in a gray color, rather thanbright white as exhibited on buttons that are “enabled”. The figuresdiscussed below will illustrate this concept many times.

User Setup:

As noted above, upon initiating a procedure the first tab 242 willpresent a sequence of titles corresponding with certain pre-bypassprocedures to be completed. As illustrated in FIG. 30A, the first suchtitle to be presented by tab 242 is “User Set Up”. While the “UserSet-Up” title is presented, the context-driven portion 243 of the thirdregion 240 presents information in both graphic and narrative formregarding steps to be completed by a user. In particular, in theembodiment shown in FIG. 30A, there are seven set-up steps presented:

-   -   1. “Insert oxygenator and venous reservoir in holders.” Together        with this narrative a graphic depiction is provided        corresponding with venous reservoir 106 and oxygenator 112 (with        heat exchanger when used) to prompt a user to mount the        reservoir 106 in mounting bracket 602 and to interconnect the        oxygenator 112 to the bracket 500.    -   2. “Snap in pre-bypass filter and venous entry module in holders        and place venous line in clamp and close cover.” Together with        this narrative a graphic depiction is presented that corresponds        with venous entry module 108 and tubing line 104 positioned        within venous line clamp 46, thereby prompting a user to        complete the tasks.    -   3. “Insert cartridge and arterial filter in holders.” Together        with this narrative instruction a graphic depiction is presented        corresponding with cartridge 120 to prompt a user to mount the        cartridge 120 in the loading assembly 21 provided in component        interface region 12, and prompting a user to place arterial        filter 118 in bracket 760 of component interface region 12.    -   4. “Connect lines to A) arterial filter, B) venous entry module,        and C) venous reservoir (2).” Together with this narrative a        graphic depiction is presented corresponding with arterial        filter 118, venous entry module 108, and venous reservoir 106,        prompting the user to connect oxygenator outlet line 116 to        arterial filter 118, venous line 104 to venous entry module 108,        purge tubing line 119 b to venous reservoir 106, and tubing line        129 to filtered input of venous reservoir 106.    -   5. “Place line in bubble sensor and close cover.” Together with        this narrative, a graphic depiction is presented corresponding        with bubble sensor 114, prompting the user to place tubing line        116 relative to bubble sensor 114.    -   6. “Place arterial and cardioplegia table lines in clamps and        close covers.” Together with this narrative, a graphic depiction        is presented corresponding with arterial valve block 196 and        cardioplegia valve block 195, prompting the user to place        arterial patient line 122 relative to arterial valve block 196,        and cardioplegia to patient line 156 relative to cardioplegia        valve block 195.    -   7. “Install pump loops and close all lids. Hang table pack on        console.” Together with this narrative, a graphic depiction is        presented that corresponds with a tubing loop (e.g., 110, 178,        190, 180, 132 or 140) positioned within a pump assembly (e.g.,        31, 32, 33, 34, 35 or 36), so as to prompt a user to complete        all tubing loop/pump installations.

As will be appreciated, the graphic depictions not only prompt a user tocomplete a given step, but additionally facilitate disposable componentrecognition and a ready review of the necessary step.

Touch screen buttons found in the lower right corner of the “Main” tabscreens being defined here are known as “navigational” buttons, in thatthey are used to navigate from one “Main” tab screen to the next, orback again. In this regard, it should be noted that the context portion243 of the “User Set-Up” tab 242 comprises a message block 245comprising the directive: “Follow instructions and then press “Load” togo to Load screen.” Correspondingly, a navigational touch screen button256 a entitled “Load” is provided that can be contacted by the user soas to proceed from “User Set-Up” procedure step, to an “Auto-Load”procedure step. The “Unload” navigational button may be used to returnthe Unload screen shown in FIGS. 30K and 30L.

Load:

When the “Load” button 256 a is pushed by user, the first tab 242 willpresent an “Auto-Load” title with the corresponding procedure-relatedinformation presented in context portion 243, as illustrated in FIG.30B. In the context portion 243 of the “Auto-Load” tab screen steps arecontemplated, (where only the first button 260 b′ is enabled initially):

-   -   1. “Load Cartridge and oxygenator”. Of note, this step is        presented in the form of a graphic button 260 b′ having touch        screen capabilities, wherein a user may simply contact the        button 260 b′ so as to cause cartridge 120 to be automatically        retracted or loading assembly 21 to be automatically advanced        into operative relation with the cartridge interface region 20,        and to cause oxygenator 112 to be automatically retracted or        moveable carriage member 511 to be automatically advanced into        operative relation with the stationary face plate 510. In this        regard, the message block 245 comprises the directive “Press        ‘Load cartridge and oxygenator’ to automatically load cartridge        and oxygenator into system.” While loading is progressing,        message block 245 may automatically display a series of messages        indicating the automatic configuration steps being completed by        control unit 10 (e.g., opening of valves, zeroing pressure        sensors, calibrating VLC 46). Block 245 may also include a        graphic, percent-of-completion or time-to-completion bar (called        a progress bar—see FIG. 30F for an example of one) that        automatically fills an outlined region in corresponding relation        to the degree of completion of task (e.g., as determined by a        comparison of elapsed time to a predetermined or predicted time        for completion). When this step is completed, a graphic        check-mark will be presented within the “Load Cartridge” button        260 b′ and the “Pressure sensor zeroed, VLC set” box, so as to        indicate to the user that these steps have been successfully        completed, and the “Load pump loops” button 260 b″ is enabled,        as shown in FIG. 30C.    -   2. “Pressure sensor zeroed, VLC set”. This narrative, presented        with a check mark, indicates that the steps described have been        successfully completed automatically upon completion of the        cartridge/oxygenator load process.    -   3. “Check pump loops, close all lids”. This narrative        corresponds with a tubing loop (e.g., 110, 178, 190, 180, 132 or        140) positioned within a pump assembly (e.g., 31, 32, 33, 34, 35        or 36), so as to prompt a user to check all tubing loop/pump        installations.    -   4. “Load Pump Loops”. Of note, this procedural step is presented        in the form of a loop touch screen button 260 b″. In this        regard, upon touching the “Load Pump Loops” button 260 b″ the        various tubing loops 110, 178, 190, 180, 132 and 140 will be        automatically loaded within the corresponding pumping assemblies        31, 32, 33, 34, 35 and 36, respectively. In this regard, while        automatic loading is being completed, message block 245 may        include the message “Loading Pump Loops.” or other messages        indicating the progress of the pump loading and circuit test        procedure. Additionally, message block 245 may include a graphic        progress bar (as described above and illustrated in FIG. 30F)        that automatically fills an outlined region in corresponding        relation to the degree of completion of the task. When pump        loading is completed, a graphic check-mark will be presented        within the Load Pump Loops button 260 b″, indicating completion        of the task, as shown FIG. 30C.    -   5. “Adjust Arterial pump to fully occluded for Prime.” Together        with this narrative a pictorial graphic is presented with        content that prompts the user to adjust the occlusion setting        wheel on the arterial pump rotor to a position that is fully        occlusive.

As illustrated in FIGS. 30B-30C, the context portion 243 of the“Auto-Load” screen tab includes a “Set-Up” graphic navigational button258 b and a “Auto-Prime” graphic navigational button 256 b having touchscreen functionality.

The “Set-Up” button 258 b is provided to permit a user to return to thepreviously described “Set-Up” tab screen shown in FIG. 30A. The“Auto-Prime” button 256 b allows a user to selectively proceed to thenext pre-bypass procedural step, but only after the various loadingprocedures contemplated by FIGS. 30B-30C have been completed.

Auto-Prime:

As shown in FIG. 30D, the “Auto-Prime” tab screen includes a contextportion 243 that identifies the following procedural steps:

-   -   1. “Spike prime and cardioplegia bags.” Together with this        narrative a corresponding graphic depiction is presented to        prompt/facilitate a user's interconnection of priming solution        bags 162, and crystalloid bags 136 to the corresponding tubing        lines interconnected with cartridge 120.    -   2. “Open water valves.” Pressing this button causes the valves        connecting the temperature control systems 330 to the oxygenator        and cardioplegia heat exchangers to be opened. After a press,        the button changes to “Close water valves” (as shown in FIG.        30E) to allow the user to reverse the process.    -   3. “Check oxygenator and cardioplegia heat exchangers for water        leaks.” Together with this narrative a pictorial graphic is        presented with content that prompts a user to operate the        heater/cooler lines connected to oxygenator 112 (e.g., via ports        519 a, 519 b to insure there are no water leaks across the blood        side of oxygenator 112 via the heat exchanger thereof, and        similarly for the cardioplegia heat exchanger. The user must        press the button labeled “Pass” to confirm that there are no        leaks, before the “Start priming” button will be valid.    -   4. “Start Priming.” This procedural step is presented in the        form of a graphic touch screen button 260 c′. Upon pushing the        button 260 c′ the various fluid circuits of disposable assembly        100 will be automatically primed with priming solution from bags        162 according to a predetermined protocol. Message block 245 may        display messages indicating the progress through the automated        priming algorithm steps, as seen in FIG. 30F. Additionally,        message block 245 may include a graphic progress bar that        automatically fills an outlined region in relation to the degree        of completion of the priming sequence steps, as seen in FIG.        30F. Upon completion of such priming, a completion check-mark        will be presented in the middle of button 260 c′, as seen in        FIG. 30G.    -   5. “Check occlusion.” Pressing this button starts the Arterial        pump occlusion setting assist algorithm, including progress        messages and progress bar in message block 245, as shown in FIG.        30H.    -   6. “Pre-Bypass Filter.” Of note, this step is presented in the        form of a touch screen button 260 c″ that will be activated and        illuminated, or highlighted upon completion of step 4 noted        above. Upon pushing the illuminated button 260 c″ the control        unit 10 will automatically initiate pre-bypass filtering of the        priming fluid through the pre-bypass filter 168 according to a        predetermined protocol. Upon completion of such pre-bypass        filtering, a completion check-mark will be presented in button        260 c″.

Upon completion of step 6, the message block 245 will read: “Pre-BypassFilter completed, press ‘Bypass’.” Correspondingly, a user may proceedto bypass operations via pushing a graphic touch screen navigationalbutton 256 c entitled “Bypass”. Alternatively, a user may go back to theprior step of “Auto-Load”, by contacting the graphic navigational button258 c presented. It should be noted that if a user determines itnecessary to proceed immediately to bypass during pre-bypass procedures,the user may contact button 256 c to interrupt the pre-bypass filteringand initiate bypass.

On Bypass:

Once the “Bypass” button 256 c is pressed, the first tab 242 willpresent the title “Main” as shown in FIG. 30I. Thereafter, the first tab242 will continue to present the “Main” title in a highlighted mannerwhen selected, until the Unload screen is activated.

As shown in FIG. 30I, “Main” tab 242 selection causes context portion243 to present narrative instructions in message box 245 and to presentgraphic touch screen buttons and other information in three rowsentitled “System”, “User Defined” and “Timers”. In particular, thenarrative box 245 would normally start with the following instruction:“To begin Bypass, turn on the arterial flow”.

At this point, the system is ready for bypass operations and the usermay proceed to interconnect the patient with the various cannulaassemblies that are interconnected with tubing line 104, arterialpatient blood line 122, cardioplegia tubing line 156 and vent tubingline 186. Additionally, prior to or at this time suction tubing lines170 and 172 will be readied for use. The patient's venous pressure willinitiate the flow of venous blood into tubing line 104 wherein the bloodis then gravity drained to venous reservoir 106. Alternatively, bloodflow may be initiated via the application of vacuum conditions atreservoir 106 or the operation of an optional pump interfacing withvenous tubing line 104. To initiate arterial, or oxygenated, blood flowto the patient a user would need to manually start arterial pump 31 oncontrol unit 10 via use of the control knob 31 a, or a pre-selectedautomated start bypass procedure as will be further described.

The user may also select other operations. For example, and asillustrated in FIG. 30I, the “System” row of graphic touch screenbuttons provide the following options:

-   -   “Pre-Bypass Filter.” Of note, this step is presented in the form        of a touch screen button 262 a. Upon pushing the illuminated        button 262 a the control unit 10 will automatically initiate        pre-bypass filtering of the priming fluid through the pre-bypass        filter 168, by a predetermined protocol and the flow set by the        user using arterial pump speed knob 31 a.    -   “System Recirc.” button 262 b: This button provides a user with        the ability to cause the recirculation of oxygenated blood        within the disposable assembly 100. When the button 262 b is        activated, pump 31 will operate with valve 92 closed causing        oxygenated blood to recirculate in a closed loop through tubing        line 119 a and 119 b (for the FIG. 3A embodiment) reservoir 106,        oxygenator 112 and arterial filter 118. Such recirculation will        occur when the button 262 b is graphically presented in a        depressed, or activated state, and will continue until the        button 262 b is further contacted, whereupon the button will be        presented in an non-depressed, or inactive, state. By way of        example, this option may be utilized after set-up procedures,        but prior to actual cannula placement.    -   “Test Arterial Connection” button 262 c: This button provides        the user with the ability to effect an automatic test of the        interconnection established between the cannula assembly        corresponding with tubing line 122 and a patient. When button        262 c is activated, with valve 92 opened and with pump 31 off,        pressure sensor 14 will sense a fluid pressure which should        correspond with the patient's blood pressure. As such, the user        may compare the sensed pressure value with a predetermined or        monitored value or range to determine if the patient        interconnection is correct. A user may momentarily operate pump        31 at a low rate while monitoring the pressure sensed by sensor        14 to further insure proper interconnection. Valve 92 must not        be left open for an extended period of time because there is a        danger of draining the patient through the under-occluded        arterial pump. Therefore, button 262 c should operate as a        press-and-hold (meaning valve 92 only stays open while the user        is holding button 262 c down) and/or logic must be included to        automatically shut the valve after a predefined time (e.g., 3-5        seconds).    -   The “System” row of buttons also includes the following buttons:    -   “Patient Info.” button 262 d: This button provides the user with        the ability to immediately access a screen comprising specific        patient vital information (e.g., height, weight, name, patient        ID or social security number, lab data, etc.). In this regard,        patient information may be input/modified via touch screen        functionalities and/or interconnection of a keyboard to control        unit 10.    -   “Log Event” button 262 e: This button provides the user the        ability to access a screen for the input/display of specific        events which a user may want to keep track of during a procedure        (e.g., drug delivery times/amounts). Again, the input of events        may be affected with touch screen capabilities and/or a keyboard        or other input device interconnected to control unit 10.    -   The “User Defined” row of graphic touch screen buttons may        comprise any of a number of features that may be pre-selected by        a user (e.g., via a “Settings” tab as described below). In the        embodiment shown in FIG. 30I the touch screen buttons provide a        user with the following control options:    -   “CPG Target” button 264 a: This button provides the user with        the ability to set the amount of cardioplegia to be dispensed to        a patient during any given increment. Upon pushing the button        264 a, the button will be presented in a depressed, or activated        state, whereupon a user may then utilize control knob 52 to set        the desired amount of cardioplegia bolus to be delivered during        the given increment. When the desired amount is displayed in the        middle to button 264 a, the user may again push button 264 a or        control knob 52 to exit the adjustment mode.    -   “CPG Delivery” button 264 b′ with “Reset” button 264 b″: Button        264 b′ provides a user with the ability to initiate the delivery        of cardioplegia to a patient upon depression of button 264 b′.        When contacted, button 264 b′ will be graphically presented in a        depressed, or activated, state, and will effect the operation of        pump 36 or both pumps 35 and 36, to achieve the desired        cardioplegia mixture (i.e., of crystalloid and blood), as may be        pre-selected by a user. Additionally, when button 264 b′ is        activated, valve 96 will be opened. Cardioplegia will then flow        to a patient through tubing line 156 until the targeted bolus        amount set via use of control button 264 a has been delivered,        whereupon cardioplegia delivery will be automatically stopped.        The amount of volume delivered (or yet to be delivered) will be        displayed on the control button, and also in the dedicated area.        A user may also manually stop cardioplegia delivery at any time        by contacting button 264 b′ or controlling knobs 35 a and/or 36        a of pumps 35 and 36, respectively. The amount of cardioplegia        delivered during a given increment will be displayed on an        updated basis in the middle of button 264 b′. To reset the        volume delivered display to a full bolus amount (e.g., after the        dispensation of an incomplete bolus of cardioplegia), a user may        push “Reset” button 264 b″. As shown in FIG. 30I, an animated        light indicator may be provided to indicate when cardioplegia is        being delivered (e.g., indicated via green illumination) and        when delivery is stopped (e.g., indicated via red illumination).    -   “Test CPG Connection” button, when depressed, holds cardioplegia        patient line valve 96 open, so that distal pressure may be read        on cardioplegia pressure sensor 18. Valve 96 must not be left        open for an extended period of time because there is a danger of        draining the patient through the CPG patient line. Therefore,        button “Test CPG Connection” should operate as a press-and-hold        (meaning valve 96 only stays open while the user is holding the        button down) and/or logic must be included to automatically shut        the valve after a predefined time (e.g., 3-5 seconds).    -   “Cardioplegia Delivery Mode” region with “Antegrade” button 264        c′ and “Retrograde” buttons 264 c″: Buttons 264 c′ and 264 c″        provide a user with the ability to select different alarm limits        for the pressure in tubing line 156 (e.g., via sensing by        pressure sensor 18) when cardioplegia is in either antegrade        and/or retrograde mode, respectively. In addition, the buttons        may tell the system to use a different pressure sensor for        alarming and/or limiting cardioplegia flow (e.g., use line        pressure for Antegrade, coronary sinus pressure for Retrograde).    -   The “Timers” row of graphic touch screen buttons can be        configured to provide a user with various display options. For        example, in the embodiment of FIG. 30I the following features        are presented:    -   “On Bypass” timer 266 a′: Timer 266 a′ provides for the        automatic display of a timed duration that a patient is        on-bypass. Timer 266 a′ may be automatically started when        arterial pump 31 is operated after priming and pre-bypass        filtering with valve 92 open. Timer 266 a′ will automatically        stop when arterial pump 31 is stopped, with valve 92 closed, and        will automatically start again when pump 31 is restarted with        valve 92 open (e.g., with the timer beginning where it left        off). The user may also manually start the On-Bypass timer        simply by depressing button 266 a′, whereupon the timer will        start. To stop the timer, a user may inactivate button 266 a′        via contact. To reset the timer, a user may contact button 266        a″.    -   “X-Clamp” button 266 b′ and timer with “reset” button 266 b″:        Button 266 b′ provides a user with the ability to time the        duration the patient has been cross-clamped during a bypass        procedure. To do so, a user may simply depress button 266 b′,        whereupon the timer will start. To stop the timer, a user may        inactivate button 266 b′ via contact. To reset the timer, a user        may contact button 266 b″.    -   “Off-Bypass” timer 266 c′: Timer 266 c′ may be provided to        provide a user with a timed duration display showing the amount        of time that a given patient has been off bypass. Timer 266 c′        may be automatically started when valve 92 is closed, and may        automatically stop when valve 92 is reopened. Timer 266 c′ will        automatically reset when started again. The user may also        manually start the Off-Bypass timer simply by depressing button        266 c′, whereupon the timer will start. To stop the timer, a        user may inactivate button 266 c′ via contact. To reset the        timer, a user may contact button 266 c″.    -   “Auxiliary” timer 266 d′ with “reset” button 266 d″: Button 266        d′ and reset button 266 d″ are provided to allow a user to        selectively time any given procedure being conducted during a        procedure. To initiate the timer, button 266 d″ may be contacted        by a user. To stop the timer, button 266 d″ may again be        contacted so as to deactivate the timer. To reset the time to        zero, reset button 266 d″ may be contacted.

When bypass is complete, the user may press the navigational button “Goto Post Bypass” to move to the Post-Bypass screen described in FIG. 30J.

Post-Bypass:

As shown in FIG. 30J, “Main” tab 242 now shows the Post-Bypass screen,which is similar to the Bypass except for the User Defined row ofbuttons and the navigational buttons. The User Defined buttons aredefined as follows:

“Fill Patient” region with “Bolus” button 264 d′ and “Deliver” button264 d″: Button 264 d′ provides a user with the ability to set a targetedamount of blood bolus to be dispensed to a patient via tubing line 122.Upon contacting button 264 d′ a user may utilize control knob 52 toestablish the desired amount of bolus to be delivered. The center ofbutton 264 d′ will present the selected amount. To exit the adjustmentmode button 264 d′ may again be pushed or control knob 52 may be pushed.In order to initiate the delivery of a bolus amount, a user may simplycontact button 264 d″. Button 264 d″ includes an illuminated display toshow the amount of bolus that has been delivered during a bolus deliveryperiod. To stop bolus delivery, a user may contact button 264 d″ so asto trigger an inactive state. Alternatively, a user may manually stopthe delivery of bolus via manual stoppage of pump 31, or just start/stopmanually within using the bolus control logic.

“Chase” region operates similarly to Fill Patient, but activates anadditional algorithm whereby as fluid is removed from the venousreservoir 108 the prime bag valves are opened to let priming solution into maintain the initial reservoir level (when Chase was initiated),thereby “chasing” blood out of the reservoir with saline.

“To Bags”: This button adds an additional mode to the Fill Patient andChase modes, whereby instead of “filling” or “chasing” blood down thearterial patient line 122, the arterial line valve stays closed, and theuser connects a transfer bag and/or hemoconcentrator to the stopcockprovided for such, and then the system is “filling” or “chasing” bloodto the bag/hemoconcentrator.

The navigational button “Return to Bypass” will move back to the Bypassscreen described in FIG. 30I. The navigational button “Move toUnloading” will move forward to the Unload screen described in FIG. 30K.

Unload:

When the “Move to Unloading” button is pushed by user, the first tab 242will present an “Unload” title with the corresponding procedure-relatedinformation presented in context portion 243, as illustrated in FIG.30K-30L.

In the context portion 243 of the “Unload” tab screen steps areincluded:

-   -   “Clamp prime and cardioplegia bag lines.” Together with this        narrative, a graphic depiction is provided corresponding with        crystalloid tubing lines 133 and prime bag lines 160 so as to        prompt a user to clamp off the bag lines before the cartridge is        disengaged from the platform.    -   “Remove pump loops.” Together with this narrative, a graphic        depiction is presented that corresponds with a tubing loop        (e.g., 110, 178, 190, 180, 132 or 140) positioned within a pump        assembly (e.g., 31, 32, 33, 34, 35 or 36), so as to prompt a        user to remove all tubing loops from the pumps.    -   “Unload cartridge.” Of note, this step is presented in the form        of a graphic button having touch screen capabilities, wherein a        user may simply contact the button so as to cause cartridge 120        to be automatically advanced away from the machine or loading        assembly 21 to be automatically retracted away from the        cartridge 120, and to cause oxygenator 112 to be automatically        advanced away from the machine or moveable carriage member 511        to be automatically retracted away from the stationary face        plate 510. In this regard, the message block 245 comprises the        directive “Complete steps below, then press ‘Unload cartridge        and oxygenator.’” While unloading is progressing, message block        245 may automatically display a series of messages indicating        the automatic configuration steps being completed by control        unit 10. Block 245 may also include a graphic progress bar that        automatically fills an outlined region in corresponding relation        to the degree of completion of task (e.g., as determined by a        comparison of elapsed time to a predetermined or predicted time        for completion). When this step is completed, a graphic        check-mark will be presented within the “Unload Cartridge and        Oxygenator” button, so as to indicate to the user that the step        has been successfully completed, as shown in FIG. 30L.

The navigational button “Post-Bypass” in FIG. 30K will be presentedbefore the cartridge is unloaded, to allow the user to move back to thePost-Bypass screen in FIG. 30J. The button will be hidden after thecartridge is unloaded (as shown in FIG. 30L), unless it is reloaded bypressing “Unload cartridge” again.

The navigational button “Set-Up” in FIG. 30L will be presented after thecartridge is unloaded, and allows the user to move back to the beginningscreen for a new case (FIG. 30A).

AV Tab:

As previously noted, the “A-V” tab 244 provides for the pictorialdepiction of components of the venous and arterial fluid circuits andinterfacing flow control and sensor components of component interfaceregion 12, as well as a plurality of touch screen control buttons. Asshown in FIG. 31A, the context driven portion 243 of the “A-V” tab 244comprises a column of touch screen buttons 262 a′-262 e′ in a firstsub-region 267, and a fluid circuit illustration in sub-region 268.Buttons 262 a′-262 e′ provide for direct user access to the samefunctionalities described above in corresponding relation to buttons 262a-262 e of FIG. 30I.

With particular reference to the fluid circuit sub-region 268, it can beseen that a number of graphic objects corresponding with components ofthe arterial-venous circuit defined by disposable assembly 100 aregraphically depicted together with graphic objects corresponding withselected flow control and sensing components provided by componentinterface region 12. The various graphic objects are presented withfluid flow lines therebetween having arrowheads to indicate thedirection of fluid flow. The fluid flow lines are color-coded toindicate venous circuit blood flow (e.g., indicated by use of blue fluidflow lines) and arterial circuit blood flow (e.g., indicated by use ofred fluid flow lines). As will be further described, certain of thegraphic objects have touch screen functionality.

In particular, the objects entitled “Venous Assembly” 270 a,“Oxygenator” 270 b, “Arterial Filter Assembly” 270 c and “Air Shunt” 270d may be contacted by a user to provide additional detail regarding thevarious corresponding components. More particularly, FIG. 31Billustrates the further componentry that will be visually representedupon contact with each of the three noted objects. Such additionalcomponentry is shown in FIG. 31B corresponding with those described inrelation to the disposable assembly 100 and component interface region12 descriptions hereinabove. Of note, it can be seen that the pictorialrepresentations corresponding with various valve assemblies areillustrated in a manner that indicates whether valve assemblies are inan open or closed state. Further in this regard, it is important to notethat the visual depictions of at least some of the valve assemblies areprovided with touch screen functionality (e.g., as indicated by athree-dimensional depiction), wherein upon contact with a given one ofsuch graphic representations, the corresponding valve assemblies withinthe component interface region 20 will automatically change its open orclosed state to the opposite state (e.g., if opened upon contact theflow control assembly will close), unless such change of state wouldpresent a predetermined undesired condition in which case a change ofstate would not be effected. In the latter case, a pop-up window mayappear describing why the change of state requested would beundesirable, but also allowing the operator to override this constraintand cause the valve to move anyway. Such functionality provides a userwith the capability to selectively, manually control the flow of fluidsthrough the system by effectively interfacing only with display 54.

Level Pop-Up:

The venous reservoir object 270 e corresponding with venous reservoir106 is also provided with touch screen functionality. More particularly,FIG. 31C illustrates a pop-up interface window 272 that will bepresented upon contact with the venous reservoir object 270 e. Suchwindow may be utilized to establish the desired level of fluid to bemaintained in venous reservoir. Such pop-up window 272 also allows auser to specify whether the desired level is to be maintained byautomatic operation of the arterial pump 31, by the venous line clamp 46within component interface region 20, or by the vacuum regulatordescribed in FIG. 11.

More particularly, as illustrated in FIG. 31C the pop-up window 272comprises the following touch screen buttons (one and only one of thefour level control buttons 272 a, 272 b, 272 f, and 272 g will bepresented in a depressed state, to show the current mode of levelcontrol):

-   -   “Art Pump” button 272 a allows a user to readily select the        option of having the desired fluid level in venous reservoir 106        established or maintained via automatic operation of arterial        pump 31. Upon activation, button 272 a will be presented in a        depressed state. To deactivate, “Off” button 272 g may be        contacted so as to turn level control off.    -   “VLC” button 272 b allows a user to readily select the option to        have the desired fluid level in venous reservoir 106 established        or maintained by the automatic operation of venous line clamp        46. Upon activation, button 272 b will be presented in a        depressed state. To deactivate, “Off” button 272 g may be        contacted so as to turn level control off.    -   “Vacuum” button 272 f allows a user to readily select the option        to have the desired fluid level in venous reservoir 106        established or maintained by the automatic operation of the        vacuum regulator, when Vacuum-Assisted Venous Drainage (VAVD) is        being used. Upon activation, button 272 f will be presented in a        depressed state. To deactivate, “Off” button 272 g may be        contacted so as to turn level control off.    -   “Off” button 272 g is used to stop level control by any method.        When no level control mode is active, button 272 g will be        presented in a depressed state.    -   “Level control=reservoir level” button 272 c allows a user to        automatically set the desired fluid level for reservoir 106 to        be whatever the then-current level is within reservoir 106. As        such, upon activation of button 272 c, level sensor 87 in the        component interface region 12 of unit 10 will detect the current        fluid level in reservoir 106 and such fluid level will be        utilized for purposes of automatic operation of arterial pump 31        or venous line clamp 46.    -   “Settings” button 272 d may be utilized by user as a shortcut to        a screen for establishing various sensor settings corresponding        with reservoir 106. For example, high level and low level        settings may be set by a user and monitored by the system to        provide for automated system response and the provision of alarm        messages as discussed hereinabove. The establishment of settings        will be further described hereinbelow.

Level control button 272 e may be utilized by a user to establish thedesired fluid level to be maintained in reservoir 106. In particular,the user may activate 272 e and then utilize control knob 52 to raise orlower the level control point. As knob 52 is manipulated, the levelcontrol button 272 e will go up and down relative to reservoir 106 toprovide a visual indication of the desired level point. Additionally,the center of level control button 272 e will illuminate with the volumesetting corresponding with the position of the level control button 272e relative to reservoir 106. Again, to exit adjustment mode, button 272e or control knob 52 may be contacted.

Pressure Pop-Up:

If a pressure sensor is contacted on the graphic depictions in thesetabs, an associated pressure sensor pop-up window is displayed. Forexample, if the arterial pressure sensor on FIG. 31B is touched, thepop-up window shown in FIG. 31D is displayed. This pop-up allows theuser to see the pressure limit and control settings, directly turnpressure control on or off for this sensor, or go to the full pressuresensor settings page (FIG. 33D) described hereinbelow by pressing the“Settings” button.

Temperature Pop-Up:

If a temperature sensor is contacted on the graphic depictions in thesetabs, an associated temperature sensor pop-up window is displayed. Forexample, if the venous temperature sensor on FIG. 31B is touched, thepop-up window shown in FIG. 31E is displayed. This pop-up allows theuser to see the temperature limit settings, or go to the fulltemperature sensor settings page (FIG. 33E) described hereinbelow bypressing the “Settings” button.

Sat/Hct Pop-Up:

If the Sat/Hct sensor on FIG. 31B is touched, the pop-up window shown inFIG. 31F is displayed. This pop-up duplicates the front panel of thestand-alone Sat/Hct device, allowing the user to standardize andcalibrate the device, or go to the full Sat/Hct sensor settings page(not shown) by pressing the “Settings” button.

CPG Tab:

Referring now to FIG. 32A, CPG tab 246 and its corresponding display areillustrated. As noted above, the CPG tab display provides informationrelating to the cardioplegia circuit defined by various components ofthe disposable assembly 100 as well as interfacing components ofcomponent interface region 12. The context region 243 of the CPG tabscreen comprises a first sub-region 267 that includes various touchscreen, graphic buttons and a second region 268 that provides a visualrepresentation of the cardioplegia circuit with objects correspondingwith various components of disposable assembly 100 and componentinterface region 12 graphically represented. In this regard, it can beseen that the circuit illustration region 268 comprises the followinggraphic objects: “CPG Cardio Outlet Assembly” 274 b and “Totals” 274 c.Each of these objects may be contacted by a user to access a moredetailed illustration of pictorial presentations of correspondingcomponents of the disposable assembly 100 and component interface region20, as shown in FIG. 32B. The graphic objects noted above areinterconnected with fluid flow lines having arrows indicating thedirection of fluid flow therebetween. Such fluid flow lines may be colorcoded in a manner to indicate the type of fluid (e.g., yellow fluid flowline indicates crystalloid and cardioplegia mixture flow and red fluidline indicates arterial blood fluid flow).

As noted the CPG tab 246 shown in FIG. 32A also includes a number ofpictorial representations corresponding with various components of thecomponent interface region 20. Such pictorial representations correspondwith cardioplegia crystalloid pump 36, cardioplegia blood pump 35,pressure sensor 18 and control valve assembly 96. Valve assembly 96representation is provided with touch screen capabilities to permitopening and closing of valve 96 upon contact. The CPG tab screen shownin FIG. 32A may include animated representations corresponding withcardioplegia crystalloid bags 136. In this regard, the volume contentswithin each of the bags 136 may be monitored on an on-going basis viainterface of the embedded processor with crystalloid pump 36 whereinvolumetric contents may be represented graphically and numerically inthe pictorial representations of the crystalloid bags 136.

Referring now to the first sub-region 267 shown in FIG. 32A, it can beseen that a plurality of graphic object buttons are presented. Severalof these buttons correspond in type and functionality with the secondrow of graphic object buttons presented in the “Main” tab screenillustrated in FIG. 30I. Additionally, of importance, a graphic buttonentitled “Ratio” 276 is presented which indicates the ratio of blood tocrystalloid solution to be established for the cardioplegia fluiddelivered to a patient utilizing the current settings. In the event thata user would like to selectively change such ratio at any time, the“Ratio” touch screen button 276 may be contacted and the user may thenutilize control knob 52 to increase or decrease the ratio to the desiredlevel (as shown in FIG. 32B), which will take effect immediately if abolus is currently in progress. Pushing in the control knob 52 orpushing or touching another area on the touch screen will exit theadjustment mode. Buttons 464 a, 464 b′ and 464 b″, and 464 c′ and 464c″, operate in the same functional manner as described above in relationto buttons 264 a, 264 b′ and 264 b″, 264 c′ and 264 c″, respectively.Further, the “Deliver Blood Only” button in FIG. 32A allows the user todeliver cardioplegia blood continuously (non-bolused) through only thecardioplegia blood pump 35, with no crystalloid added (non-ratioed),until the “Deliver Blood Only” button is touched again to terminate theblood only mode.

As noted above, the “CPG Cardio Outlet Assembly” object 274 b and“Totals” object 274 c of the CPG tab screen shown in FIG. 32A may becontacted by a user. FIG. 32B illustrates the additional informationthat would be conveyed upon contact with each of the two objects.

Suction/Fluids Tab:

Continuing now to FIG. 32C, the “Suction/Fluids” tab screen andcorresponding context driven display region 243 is presented. Region 243provides graphic representations corresponding with a first suctiontubing line 170 and corresponding pump 32, the second suction line 172and corresponding suction pump 34 and the left ventricle tubing line 186and corresponding pump 33, along with the three negative pressuresensors associated with these three suction/vent lines. Also depictedare the sequestration reservoir and sequestration drain valve, the twovalves that direct the vent pump to either reservoir, and prime bags andassociated prime bag valves, and the reservoir filter pressure sensor.

In the alternative circuit embodiment shown in FIG. 3B, a modified userinterface could contain the following buttons (not shown):

-   -   “Hemoconcentrator to Reservoir” button allows a user to initiate        automated hemoconcentration, wherein upon contacting the button        pumps 37 and 38 will operate at pre-selected rates to pump the        hemoconcentrated blood to reservoir 106.    -   “Hemoconcentrator to Transfer Bag” button allows a user to        initiate automated hemoconcentration, wherein upon contacting        the button pumps 37 and 38 will operate at pre-selected rates to        pump the hemoconcentrated blood to transfer bag 194.    -   “Transfer Bag to Reservoir” button allows a user to selectively        initiate the flow of fluid from transfer bag 194 to reservoir        106.    -   “Reservoir to Transfer Bag” button: This button allows a user to        selectively effect the transfer of fluid from reservoir 106 to        transfer bag 194.    -   “Off” button allows a user to stop any and all of the functions        associated with the four buttons listed above.

Gases Tab:

FIG. 32D illustrates the “Gases” tab 250 and a corresponding contextdriven region 243. Again the context driven portion 243 includes a firstsub-region 267 with a plurality of touch screen buttons 468 a-468 c, anda second sub-region 268 which presents a visual representation of a gascircuit servicing oxygenator 112.

Waveforms Tab:

FIG. 32E illustrates the “Waveforms” tab 252 and corresponding contextdriven region 243. Again, the context driven portion 243 includes afirst sub-region 267 with a plurality of touch screen buttons 282 a-282c, and a second sub-region 268 which presents a visual representation ofone or more monitored waveforms. More particularly, button 282 a may becontacted to access a screen which allows the user to select sensors forwhich corresponding monitored waveforms are to be presented. The usermay select from a plurality of sensors, including for example, sensorsto monitor a patient's temperature, blood pressure and ECG readings.Upon selection of a sensed parameter for waveform presentation, the usermay utilize buttons 282 b and 282 c to enlarge and reduce, selectively,a given portion of the presented waveforms.

FIG. 32E also shows a “Backward” button, that, for trending waveforms,allows the user to display waveform activity earlier in time than thatcurrently shown, and a “Forward” button that allows the user to returnforward to the waveforms showing data currently being collected.

Settings Tab:

Finally, FIGS. 33A-33F illustrate the “Settings” tab 254 andcorresponding context driven region 243 options accessible to a user. Inparticular, the context-driven portion 243 shown in FIGS. 33A-33Fincludes a first sub-region 284 comprising a row of touch screenbuttons, and a second sub-region 286 which provides a listing of furthertouch screen options corresponding with the particular button 284 a-284f within sub-region 284 that has been contacted by user.

Protocol Settings:

For example, FIG. 33A shows a second sub-region 286 that would bepresented upon contact with the “Protocol” button 284 a presented in thefirst sub-region 284. A “Protocol” is a named, stored set of all theparameter settings that may be established by the user through thesettings pages described hereinbelow. This includes all sensor limitsettings, configuration of user-defined and configurable sections of thescreen, and all other settings from these screens. The “CurrentProtocol” item 286 a at the top of sub-region 286 indicates the name ofthe last protocol that was established for current use (“Loaded”), andwill also have a asterisk next to it if any parameters settings havebeen modified since the last protocol was loaded. Such settingmodifications are temporary, and will be overwritten if another (or thesame) named protocol is loaded. Such temporary settings may save into anew or existing protocol with the “Save Protocol” control 286 edescribed below.

The touch screen options presented in the second sub-region 286 allow auser to select a protocol set to establish upon power-up of the machine(the “Wake-Up” protocol 286 b), establish a different named protocol tobe used currently (“Load Protocol” 286 c), examine the details of anynamed protocol (“Display Protocol” 286 d), and save the current settingsas a new named protocol (“Save Protocol” 286 e). Contacting the downarrow (286 b′, 286 c′, 286 d′, 286 e′) to right of each of these fourcontrols displays what is known as a “pull-down list”, which drops downon top of whatever is below, and provides a scrollable list of allcurrently saved named protocols, including one or more “Factory Default”protocols which are pre-set at the factory, and may not be modified.Selecting a protocol from one of these four lists causes the namedprotocol to be established as the Wake-Up protocol, loaded as thecurrent protocol, have its parameters displayed, or be overwritten withthe current parameter settings, respectively. Additionally, the “SaveProtocol” pull-down list will have an item called “New”, which, whenselected, will allow the user to save a new protocol, and give it a newname using an externally connected or on-screen alphanumeric keyboard.

Sensor Settings:

In order to adjust individual component settings, a user may contact oneor more of the other buttons of the first sub-region 284. For example,upon contact with the “Sensors” button 284 b represented in the firstsub-region, the options set forth in FIG. 33B will be presented. In thisregard, and as shown in FIG. 33B, the various sensors may be grouped asfollows: “air detectors”, “pressure sensors”, “level detectors”,“blender/gas”, “temp. sensors” and “SAT/HCT”. The various sensors thatcorrespond with each of these categories may be presented via contactwith an adjacent down arrow button, wherein a full listing of thevarious sensors comprising a given group will be listed, each withcorresponding buttons. This is demonstrated in FIG. 33C with the airdetectors pull-down list. The user may then contact the graphic buttoncorresponding with a given sensor to establish the desired settings. Byway of example, FIG. 33D illustrates the display accessible when a usercontacts the button for “Arterial Line” pressure sensor, and FIG. 33Eillustrates the display accessible when a user contacts the button for“Venous” temperature sensor.

Pressure Sensor Settings:

As shown in FIG. 33D, a number of arterial pressure settings can beestablished. In particular, the display corresponding with FIG. 33Dprovides for establishing four different, predetermined pressuresettings to be monitored by pressure sensor 14. In order to modify agiven setting, a user may simply contact the corresponding set button(e.g., the “low warning”) button and then establish the desired settingvia control knob 52. As the control knob 52 is adjusted, thecorresponding pressure setting button will move along the depictedpressure scale. When the desired pressure setting has been reached, auser may again push the corresponding pressure setting button or controlknob 52. In addition to setting the desired pressure levels, a user mayfurther select from a variety of sensor control functions as indicatedby the various touch screen buttons.

Temperature Sensor Settings:

As shown in FIG. 33E, a number of venous temperature settings can beestablished. In particular, the display corresponding with FIG. 33Eprovides for establishing high and low alarm limit settings to bemonitored by the venous temperature sensor in venous entry module 108.Settings methods and options are similar to those described for FIG.33D.

As will be appreciated, similar screens may be provided for establishingthe settings of and control over the operation of the various othertypes of sensors comprising control unit 10, and generally noted by thegroups indicated by FIG. 33B.

CPG Settings:

FIG. 33F—CPG Settings (accessed from CPG button 284 c on Settings tabFIG. 33A) gives the ability to specify the constituents, startingvolume, and default ratio for the crystalloid bags, and change the bolusmode between volume, time or continuous, count up or count down, as wellas other settings.

More Settings (not Shown):

Timers button 284 d on Settings tab FIG. 33A accesses a Timer Settingsscreen that gives timer on/off time/date tracking history, and theability to set timer alarms.

Pulse button 284 e on Settings tab FIG. 33A accesses a Pulsatile FlowSettings screen that lets the user set the Pulsatile flow parameters forthe arterial pump, such as BPM, duty cycle, and baseline flow.

Other button 284 f on the Settings tab FIG. 33A accesses a MiscellaneousSettings screen that lets the user set the system date and time,language to use, and other miscellaneous settings.

VIII. Summary of Control Protocols and Algorithms

The perfusion system uses automated procedures described below.

1. Auto Prime

The “Auto-Prime” procedure, initiated by contacting graphic button 260c′ on the “Auto-Prime” tab screen shown in (FIG. 30D) will result in theautomatic priming of the venous, arterial and cardioplegia fluidcircuits. As will be appreciated, the automatic priming will becontrolled in accordance with predetermined protocols stored in memory,and will entail automated steps.

Such steps will include the opening/closing of the priming solutionvalves 98 so as to cause the priming solution to flow through theintegral passageway 164 of cartridge 120 and line 129 into the venousreservoir 106 and fill the venous reservoir 106 to a predeterminedvolume. Operation of the arterial pump 31 and the opening/closing of thevarious valve assemblies on control unit 10 will be completed accordingto the predetermined protocols so as to prime line 110, oxygenator 112,line 116, arterial filter 118, arterial patient line 122, venous patientline 104, venous entry module 108, pre-bypass filter 168, line 166 andthe air purge tubing line 119 a, integral passageways 309 a and 309 b ofcartridge 120, and line 119 b.

In this regard, it should be noted that the disposable assembly 100 willinitially provide for a fluid interconnect between arterial patienttubing line 122 and venous tubing line 104, wherein the priming solutionmay flow through patient tubing line 122, connector 175 and into venoustubing line 104. As will be appreciated, venous line clamp 46 and valveassembly 95 may be employed to direct the priming fluid through tubinglines 166 and 104 for priming purposes. Connector 175 will be disposedfor selective removal after priming when patient interconnect for bypassis desired.

The automatic priming protocol will include inverting the arterialfilter 118 and reinverting the arterial filter 118 to the up-rightposition multiple times during the priming sequence to facilitatepriming and removing air from the arterial filter. As priming of thearterial filter 118 is initiated, the filter will be inverted byrotating mounting arm 762 as previously described herein such that theinlet from line 116 and air purge outlet connecting to line 119 a of thearterial filter is down, and the outlet connecting to line 122 of thearterial filter is at the top. During the bypass procedure the arterialfilter inlet and air purge outlet are located on the top of the arterialfilter and the outlet is located at the bottom of the arterial filter.As previously described, initially during the automatic primingprocedure the arterial filter is inverted. Flow enters the arterialfilter from the inlet and due to the inverted positioning of thearterial filter the flow fills the arterial filter from the bottom upforcing air to naturally rise to the top of the arterial filter and outthe outlet of the arterial filter. At some point after the arterialfilter has been primed in the described manner the arterial filter isreinverted to the up-right position where air in the arterial filter canrise to the top and be purged out line 119 a. The inverting andreinverting to the upright position is repeated multiple times at highand/or low flow rates to ensure the arterial filter is completely primedand air is removed.

Automatic priming will also entail the selective operation ofcardioplegia blood pump 35, cardioplegia crystalloid pump 36, arterialpump 31 and the selective opening/closing of appropriate valvescomprising control unit 10 so as to direct priming solution from venousreservoir 106 through tubing line 128, and integral passageway 130. Suchoperation will effect priming of the cardioplegia circuit portionincluding integral passageways 142, and 150, tubing lines 146,cardioplegia heat exchanger 148, bubble trap 152 as well as tubing loop132. Similarly, the cardioplegia tubing line 156 will be primed throughconnector 175 fluidly interconnected with venous line 104 and returningfluid to venous reservoir 106. Similarly, the cardioplegia crystalloidcircuit including crystalloid lines 133, integral passageways 138, and142, and tubing loop 140 will be primed with crystalloid solution.

2. Pre-Bypass Filter

After the “Auto-Prime” procedures, a user may contact the “Pre-BypassFilter” button 260 c″ illustrated in (FIG. 30H), thereby causing thepriming solution present in the arterial-venous circuit to be filteredvia passage through pre-bypass filter 168 for a user selected time at auser selected flow rate by operation of arterial pump 31. In particular,valve 46 will close and valve 95 will open, thereby diverting primingsolution which flows into venous entry module to flow through the prebypass filter 168 and line 166 into venous reservoir 106. The primingsolution may then circulate from venous reservoir 106 through tubinglines 110, 116, and 122, and through the connector 175 thatinterconnects arterial patient line 122 and venous line 104, throughvenous entry module 108 and back to pre-bypass filter 168.

Additionally, while pre-bypass filtering described herein above, thecardioplegia blood pump 35 may be operated causing the priming solutionin the cardioplegia circuit to flow through pre-bypass filter 168. Inparticular, cardioplegia blood pump 35 may be operated and valve 96opened thereby causing the priming solution to be diverted through line128, integral passageways 130, 142, 150; tubing lines 146, pump tubingloop 132, cardioplegia patient line 156, through connector 175, and intothe venous line 104 for return to the pre-bypass filter 168.

3. Start/Stop Bypass

To initiate bypass, the various cannula assemblies provided oncardioplegia tubing line 156, venous tubing line 104 and arterial tubingline 122 may be located as appropriate within the body cavity of thepatient.

Thereafter, to initiate actual bypass blood flow, venous line clamp 46may be manually operated by contacting graphic button 222 a or button222 b and adjusting knob 52 to initiate and sustain the necessary flowof venous blood through tubing line 104 to venous reservoir 106.Arterial pump 31 may also be manually operated by adjusting knob 31 aand automatically or manually opening valve 92 to initiate and sustainthe necessary flow to return blood to the patient through arterialpatient line 122.

Additionally, while a user may start or stop a bypass procedure viamanual control of venous line clamp 46 and arterial pump 31 and valve92, a user may initiate an automatic start or stop bypass procedure. Theautomatic start procedure, initiated and/or enabled by contacting agraphic button (not shown) on user interface 50, will result in theautomatic start of the arterial pump 31 and/or the automatic opening ofthe venous line clamp 46. As will be appreciated, the automatic startprocedure will be controlled in accordance with predetermined protocolsstored in memory, and will entail automated steps. The control unit 10may then begin automated start or automated stop of the bypass procedureif the procedure is currently in progress. For example, at the outset ofbypass, the starting up of arterial pump 31 is controlled according to apredetermined ramp rate protocol. Such ramp rate, the speed or flowincrease per unit time, may be selected by a user by contacting graphicbuttons (not shown) and/or adjustment of knob 52 on user interface 50tab 254. Similarly, at the outset of bypass, the opening of the venousline clamp 46 may occur according to a predetermined ramp rate protocolstored in memory after contacting a graphic button (not shown) on userinterface 50. Such ramp rate, the opening rate per unit time, may beselected by a user by contacting graphic buttons (not shown) and/oradjustment of knob 52 on user interface 50.

The automatic/manual operation described herein above of the venous lineclamp 46 and arterial pump 31 to start bypass may occur in anycombination. More specifically bypass may be initiated by manualoperation of both the venous line clamp 46 and arterial pump 31, manualoperation of the venous line clamp 46 with automatic operation of thearterial pump 31, automatic operation of the venous line clamp 46 withmanual operation of the arterial pump 31, or automatic operation of boththe venous line clamp 46 and arterial pump 31.

The manual/automatic methods herein described above to start bypass maybe similarly used to stop the bypass procedure. More specifically, thevenous line clamp 46 may be manually operated to reduce or terminate theflow of blood from the patient and the arterial pump 31 may be manuallyoperated to reduce or terminate the flow of blood to the patient asnecessary to stop bypass. Similarly, the automatic means to start bypassthrough the automatic operation of the venous line clamp 46 and thearterial pump 31 may be used to stop bypass using the ramp methodsdescribed herein above to reduce or terminate the blood flow to or fromthe patient as necessary to stop bypass. The manual and automatic rampmethods of operating the venous line clamp 46 and arterial pump 31described herein above to start or initiate bypass may also be used inthe same combinations as described herein above to reduce or terminateflow as necessary to stop bypass.

4. Auto Start/Stop Bypass Using Venous Line Clamp to Control VenousReservoir Level

This is a method of either starting or stopping bypass while maintainingthe venous reservoir 106 level at a pre-selected value throughincreasing or decreasing the amount of restriction of the venous line104 using venous line clamp 46 control. More specifically, prior toinitiating bypass, the user would select the desired venous reservoirlevel to maintain while starting bypass by contacting graphic buttons(not shown) and/or adjusting knob 52 on user interface 50. Thepre-selected venous reservoir level could be set to the currentreservoir level, or a reservoir level either above or below the currentlevel as desired by the user. The venous line clamp reservoir levelcontrol procedure, initiated and/or enabled by contacting a graphicbutton (not shown) on user interface 50, will result in venous reservoirlevel control by automatic opening or closing of venous line clamp 46.As will be appreciated, the automatic level control will be controlledin accordance with predetermined protocols stored in memory, and willentail automated steps.

As bypass is started, the user would manually operate the arterial pump31 to begin bypass flow and slowly or quickly increase flow to the userdesired flow rate. While the user started flow by increasing the speedthrough operation of knob 31 a on arterial pump 31, the venous lineclamp 46 would automatically begin to open to the amount necessary tomaintain the venous reservoir 106 level at the pre-selected value. Asthe venous reservoir level fluctuates either due to adjustment of thearterial pump 31 flow rate or due to other volumetric changes in thepatient or bypass circuit, venous line clamp 46 would automaticallyincrease or decrease the amount of restriction in venous line 104 toeither increase or decrease the flow into the venous reservoir tomaintain the venous reservoir level at the pre-selected value.

Conversely, in order to stop bypass, the venous line clamp reservoirlevel control procedure, initiated by contacting a graphic button (notshown) on user interface 50, will result in venous reservoir levelcontrol by automatic opening or closing of venous line clamp 46. Priorto stopping bypass, the user would select the desired venous reservoirlevel to maintain while stopping bypass by contacting graphic buttons(not shown) and/or adjusting knob 52 on user interface 50. While theuser decreases the flow by reducing the arterial pump flow rate throughoperation of the knob 31 a on arterial pump 31, the venous line clamp 46would automatically begin to close to the restriction necessary tomaintain the venous reservoir 106 level at the pre-selected value. Asthe venous reservoir level fluctuates either due to continued slow downof the arterial pump 31 flow rate or due to other volumetric changes inthe patient or bypass circuit, venous line clamp 46 would automaticallydecrease or increase the amount of restriction in venous line 104 toeither increase or decrease the flow into the venous reservoir tomaintain the venous reservoir level at the user pre-selected value.

5. Auto Start/Stop Bypass Using Arterial Pump to Control VenousReservoir Level

This is a method of either starting or stopping bypass while maintainingthe venous reservoir 106 level at a pre-selected value throughincreasing or decreasing the flow into and out of venous reservoir 106through automatic control of arterial pump 31 flow rate. Morespecifically, prior to initiating bypass, the user would select thedesired venous reservoir level to maintain while starting bypass bycontacting graphic buttons (not shown) and/or adjusting knob 52 on userinterface 50. The pre-selected venous reservoir level could be set tothe current reservoir level, or a reservoir level either above or belowthe current level as desired by the user. The arterial pump reservoirlevel control procedure, initiated and/or enabled by contacting agraphic button (not shown) on user interface 50, will result in venousreservoir level control by automatic increasing or decreasing flow ofarterial pump 31. As will be appreciated, the automatic level controlwill be controlled in accordance with predetermined protocols stored inmemory, and will entail automated steps.

As bypass is started, the user would manually begin to open venous lineclamp 46 to begin bypass flow and slowly or quickly increase venous flowto the user desired flow rate. While the user started flow by decreasingthe restriction in venous line 104 through manual operation of venousline clamp 46, the arterial pump 31 would automatically begin toincrease flow to the amount necessary to maintain the venous reservoir106 level at the pre-selected value. As the venous reservoir levelfluctuates either due to adjustment of venous line clamp 46 or due toother volumetric changes in the patient or bypass circuit, arterial pump31 would automatically increase or decrease the amount of flow 104 toeither increase or decrease the flow out of the venous reservoir tomaintain the venous reservoir level at the pre-selected value.

Conversely, in order to stop bypass, the arterial pump reservoir levelcontrol procedure, initiated by contacting a graphic button (not shown)on user interface 50, will result in venous reservoir level control byautomatic increasing or decreasing flow by operation of arterial pump31. Prior to stopping bypass, the user would select the desired venousreservoir level to maintain while stopping bypass by contacting graphicbuttons (not shown) and/or adjusting knob 52 on user interface 50. Whilethe user decreases the flow into the venous reservoir 106 by reducingthe restriction in venous line 104 through manual operation of thevenous line clamp 46, the arterial pump 31 would automatically begin toreduce flow to the amount necessary to maintain the venous reservoir 106level at the pre-selected value. As the venous reservoir levelfluctuates either due to continued restriction of venous line 104through operation of venous line clamp 46 or due to other volumetricchanges in the patient or bypass circuit, arterial pump 31 wouldautomatically decrease or increase the flow exiting venous reservoir 106to maintain the venous reservoir level at the pre-selected value.

6. Cardioplegia Pressure Protection

The “Cardioplegia Pressure Protection” procedure, initiated and/orenabled by contacting a graphic button (not shown) on user interface 50will result in the automatic control of cardioplegia pumps 35, 36 toprevent negative pressure occurring on oxygenator 112. As will beappreciated, the automatic cardioplegia pressure protection procedurewill be controlled in accordance with predetermined protocols stored inmemory, and will entail automated steps.

If enabled, the cardioplegia pressure protection procedure may providean automated monitoring function, wherein if the pressure in thearterial tubing line 122, as monitored by pressure sensor 14 falls belowa predetermined low limit, the cardioplegia blood pump 35 and/orcrystalloid pump 36 will automatically slow down while maintaining theirrespective flow rate ratios such that the flow of the cardioplegia bloodpump 35 does not cause the pressure in line 122 as monitored by pressuresensor 14 to fall below a predetermined low pressure limit.Alternatively, if the pressure monitored by pressure sensor 14 fallsbelow a predetermined low limit, the cardioplegia blood pump 35 and/orcrystalloid pump 36 will automatically stop. Such automatic controlreduces the risk that a negative pressure will act upon the membranewithin the oxygenator 112 so as to introduce air into the arterialblood. If the pressure monitored by pressure sensor 14 falls below apredetermined low pressure limit an alarm will occur on user interface50.

7. Cardioplegia-Arterial Pump Interlock

The “Cardioplegia-Arterial Pump Interlock” procedure, initiated and/orenabled by contacting a graphic button (not shown) on user interface 50will result in the automatic control of cardioplegia pumps 35, 36 toprevent negative pressure occurring on oxygenator 112. As will beappreciated, the automatic cardioplegia-arterial pump interlockprocedure will be controlled in accordance with predetermined protocolsstored in memory, and will entail automated steps.

If enabled, the cardioplegia-arterial pump interlock procedure mayprovide an automated monitoring function, wherein if the arterial pumpstops or slows to a flow rate below the flow rate of the cardioplegiablood pump 35, the cardioplegia blood pump 35 and/or the crystalloidpump 36 may stop. Alternatively, if the arterial pump stops or slows toa speed or flow rate below the flow rate of the cardioplegia blood pump35, the cardioplegia blood pump 35 and/or the crystalloid pump 36 mayslow down to a combined flow rate, while maintaining their respectiveflow rate ratios, such that the cardioplegia blood pump 35 flow rate isless than the arterial pump flow rate 31. Such automatic control reducesthe risk that a negative pressure will act upon the membrane within theoxygenator 112 so as to introduce air into the arterial blood.

8. Post Bypass Fluid Recovery

Upon completion of a bypass procedure, additional automated operationsmay be completed. For example, specific protocols may be followed torecover as much usable blood as possible from the fluid circuits. Suchprocedures may include the drainage of blood from a sequestrationreservoir 301 into venous reservoir 106 via selective control over valve401 by contacting a graphic button (not shown) on user interface 50.Additionally, a user may drain blood from the venous tubing line 104into the venous reservoir 106 by opening venous line clamp 46 bycontacting graphic buttons (not shown) and/or adjusting knob 52 on userinterface 50. Cardioplegia blood pump 35 and arterial pump 31 may alsobe selectively operated in reverse by contacting graphic buttons (notshown) on user interface 50 resulting in the automatic operation ofcardioplegia blood pump 35 and arterial pump 31 and cardioplegia patientline valve 96. As will be appreciated, the procedure will be controlledin accordance with predetermined protocols stored in memory, and willentail automated steps by contacting graphic buttons (not shown) on userinterface 50 as to empty the cardioplegia circuit blood through integralpassageway 130 to tubing line 128, arterial filter 118, tubing lines 116and 118, and back into the venous reservoir 106. The collected bodyfluid may then be diverted to a transfer bag through valve 311 orthrough line 122 or through connection directly to an autologous bloodsalvage device for subsequent washing for later return to the patient.

9. Sequestration Level Sensing

The “Sequestration Level Sensing” procedure, initiated and/or enabled bycontacting a graphic button (not shown) on user interface 50, willresult in the automatic control of suction and vent pumps 32, 33, and 34and/or sequestration drain valve 401 to prevent over filling of thesequestration reservoir. As will be appreciated, the automaticsequestration level sensing procedure will be controlled in accordancewith predetermined protocols stored in memory, and will entail automatedsteps.

If enabled, the sequestration level sensing procedure may provide anautomated function. If the lower level sensor 322 detects fluid anadvisory alarm occurs to alert the user that the level in sequestrationreservoir 301 is rising. The user may then open drain valve 401 andempty the contents through integral passageway 305 and tubing line 129into the venous reservoir 106 or drain off contents to a transfer bag orcell washing device through manual valve 303.

If the higher level sensor 320 detects fluid an advisory alarm occurs atuser interface 50 indicating that sequestration reservoir 301 is full.The sequestration drain valve 401 automatically opens causing thecontents of sequestration reservoir 301 to flow into venous reservoir106 until the fluid level drops below the lower level sensor 322 oruntil all suction pumps are stopped. Alternatively, if the operatorprefers that the sequestered blood not be automatically added to thevenous reservoir, the suction pumps 32 and 43 could be selectivelystopped automatically. The vent pump 33 could also be automaticallystopped or the fluid re-routed to the venous reservoir 106 throughintegral passageway 192 b and line 129 by opening valve 403 and closingvalve 402.

The user options described herein above could be selected by contactinggraphic buttons (not shown) on user interface 50 to enable the desiredoptions.

10. Automatic Air Shunt

The “Automatic Air Shunt” procedure will result in the automaticshunting of air through automatic control of arterial pump 31 and valves405 and 406 to remove air from the circuit and prevent air from enteringthe patient. As will be appreciated, the automatic air shunt procedurewill be controlled in accordance with predetermined protocols stored inmemory, and will entail automated steps.

When a predetermined small amount of air (i.e., small amount of air is agiven volume of air in a given amount of time where most of the airwould flow through the air shunt circuit line 119 a, integralpassageways 309 a and optionally 309 b and line 119 b without asignificant amount of air entering the arterial filter then transitingthe arterial filter medium and exiting the arterial filter), is detectedat oxygenator bubble sensor 114 the high flow arterial filter purgevalve 406 and optionally the low flow arterial filter purge valve 405opens and the air/fluid is routed through line 116, arterial filter 118,line 119 a, integral passageways 309 a and/or 309 b, line 119 b tovenous reservoir 106. An alarm condition will be generated and displayedon user interface 50. Valve 406 and optionally valve 405 remain openuntil a predetermined amount of time after no air is present at thebubble sensor 114 to ensure that all air is removed from the circuit.

When a predetermined large amount of air (i.e., large amount of air is agiven volume of air in a given amount of time that would exceed theamount of air that could flow through the air shunt circuit line 119 a,integral passageways 309 a and optionally 309 b and line 119 b resultingin a significant amount of air entering the arterial filter andtransiting the arterial filter medium then exiting the arterial filterand potentially into the arterial patient line 122), or a continuousamount of small air is detected at oxygenator bubble sensor 114 the highflow arterial filter purge valve 406 and optionally low flow arterialfilter purge valve 405 opens and the air/fluid is routed through line116, arterial filter 118, line 119 a, integral passageways 309 a and/or309 b, line 119 b to venous reservoir 106. Additionally, arterial pump31 slows to a flow that will not generate a pressure that exceeds apredetermined value as seen at pressure sensor 114 and valve 92 isclosed. An alarm condition will be generated and displayed on userinterface 50. After a predetermined amount of time after no air ispresent at bubble sensor 114 valves 406 and optionally valve 405 close.After the air condition has cleared, valve 92 is opened and arterialpump speed returns to the pre-air flow rate either automatically ormanually by the user. Alternatively, instead of slowing down arterialpump 31, arterial pump 31 may be stopped and valve 92 closed.

In each case where the arterial pump 31 is slowed or stopped and valves405 and 406 opened or closed, the user can override the automatedprocedure by contacting graphic buttons (not shown) on user interface 50which returns the arterial pump and/or valves to their pre automatic airshunt condition settings.

If the arterial line pressure as measured at pressure sensor 14 is notsufficiently high enough to prevent retrograde flow of air through purgevalves 405 and 406, valves 405 and 406 could be closed if the arterialline pressure falls below a predetermined value.

In addition, when air is detected at bubble sensor 114 bloodcardioplegia delivery is automatically interrupted to prevent air fromreaching the cardioplegia system if the amount of air exceeds apredetermined amount that could transition the arterial filter andpotentially enter the cardioplegia blood supply line 128.

11. Automatic Fill Patient

The “Automatic Fill Patient” procedure, initiated and/or enabled bycontacting graphic button 264 d″ on user interface 50 will result in theautomatic control of arterial pump 31 and arterial patient line valve 92to deliver preselect volume to the patient. As will be appreciated, theautomatic fill patient procedure will be controlled in accordance withpredetermined protocols stored in memory, and will entail automatedsteps. The user would select the desired volume to transfer to thepatient by contacting graphic buttons (not shown) and/or adjusting knob52 on user interface 50.

If enabled, this protocol automatically returns fluid to the patient ata user-selected bolus volume and flow rate at the end of the procedure.The user initiates the auto fill procedure by touching the 264 d″buttonat the user interface 50. This automatically causes arterial line valve92 in arterial patient line 122 to open and arterial pump 31 to run atthe user-selected flow rate set at control knob 31 a. After the selectedbolus volume is delivered the arterial pump 31 stops and valve 92 isclosed. As the bolus is delivered, the current, and/or accumulatedamount can be displayed on user interface 50.

12. Positive and Negative Pressure Control

The “Pressure Control” procedures, initiated and/or enabled bycontacting a graphic button (not shown) on user interface 50 will resultin the automatic control of any pump to control the pressures in therespective pump circuits. As will be appreciated, the pressure controlprocedures will be controlled in accordance with predetermined protocolsstored in memory, and will entail automated steps. The user would selectthe desired pressure control settings by contacting graphic buttons (notshown) and/or adjusting knob 52 on user interface 50.

This control protocol is useful to control pressure in various circuitsin the perfusion system by controlling pump speed. This controlalgorithm may be used in any pump circuit. This is more desirable thanstopping the pumps on an overpressure condition since a complete stop ofthe pump results in completely stopping fluid flow in the circuit andpotentially creating vastly fluctuating pressures.

This control protocol allows the pump to be controlled to a speed lowerthan its user-set speed in order to control to a programmable set pointpressure. This pressure set point may be either positive (for arterialor cardioplegia pumps) or negative (for suction or vent pumps). Themaximum pump speed is the user-set speed at pump knobs 31 a-36 a. Thepump will run at this speed unless the measured pressure increases overthe set point pressure (or decreases below the set point for negativepressure control.). When measured pressure exceeds set point pressure apressure control loop is enabled. Use of this control algorithm requiresa pressure transducer calibrated in appropriate units, having anappropriate sample rate (i.e., 40 Hz).

The monitored pressure is used as a feedback control parameter toautomatically adjust pump speed to maintain pressure at the controlpoint. In the event the monitored pressure falls outside of user setlimits an alarm/indication may be provided at interface 50 and/or thespeed of one or more (e.g., both cardioplegia pumps simultaneously) iseither increased or decreased in order to maintain the desired pressure.For example, the user may set at the user interface a high pressurelimit of 150 mmHg, a low pressure limit of 20 mmHg and a control pointof 100 mmHg. By utilizing the monitored pressure as a feedback controlparameter the system will automatically adjust the speed of the pumps tomaintain pressure at the control point. If the pressure exceeds for anyreason the upper or lower limit an alarm is activated at the userinterface.

13. Venous Reservoir Level Control by Arterial Pump

The venous reservoir level control by arterial pump procedure, initiatedand/or enabled by contacting a graphic button (not shown) on userinterface 50 will result in the automatic control of arterial pump 31 tomaintain the desired level or volume in the venous reservoir. As will beappreciated, the level control procedure will be controlled inaccordance with predetermined protocols stored in memory, and willentail automated steps. The user would select the desired venousreservoir level to maintain by contacting graphic buttons (not shown)and/or adjusting knob 52 on user interface 50.

This control protocol maintains the level in the venous reservoir 106 ata pre-selected value by controlling the speed of arterial pump 31. Thecontinuous level control is an operational mode by which the level ofthe reservoir is not allowed to increase above or decrease below thepre-selected value which can be adjusted by the user. Use of this moderequires that a continuous level sensor such as that described withrespect to FIG. 12 is present on the system to provide feedback of thecurrent level of fluid in the reservoir. The pump's maximum flow rate isset by the user at pump knob 31 a. As the level increases above ordecreases below the pre-selected value, a software and/or hardwareimplemented PID (Proportional, Integral, Differential) servo slows thepump down or speeds up the pump and adjusts the pump speed to maintainthe pre-selected reservoir level resulting in the flow rate out of thereservoir closely matching the flow into the reservoir. If the flow intothe reservoir increases substantially, then the level may rise above theset point because the pump flow rate is limited by the setting of thepump knob 31 a.

The advantage of this method of level control is that the level in thereservoir can be controlled to any level. The level can also be changedat any time and there will be a smooth transition between the old andnew levels. Use of the pump continuous level control system alsoincreases patient safety because it will prevent emptying of the venousreservoir 106 in case of temporary user inattention.

14. Venous Reservoir Level Control by Venous Line Clamp

The venous reservoir level control by venous line clamp procedure,initiated and/or enabled by contacting a graphic button (not shown) onuser interface 50 will result in the automatic control of venous lineclamp 46 to maintain the desired level or volume in the venousreservoir. As will be appreciated, the level control procedure will becontrolled in accordance with predetermined protocols stored in memory,and will entail automated steps. The user would select the desiredvenous reservoir level to maintain by contacting graphic buttons (notshown) and/or adjusting knob 52 on user interface 50.

This control protocol maintains the level in the venous reservoir 106 ata pre-selected value by controlling the venous line clamp 46. Thecontinuous level control is an operational mode by which the level ofthe reservoir is not allowed to decrease below or increase above somepre-selected value which can be adjusted by the user. Use of this moderequires that a continuous level sensor such as that described withrespect to FIG. 12 is present on the system to provide feedback of thecurrent level of fluid in the reservoir. As the level increases above ordecreases below the pre-selected value, a software and/or hardwareimplemented PID (Proportional, Integral, Differential) servo partiallyor completely opens or closes venous line clamp 46 to maintain thepreselected reservoir level resulting in the flow rate into thereservoir closely matching the flow out of the reservoir.

The advantage of this method of level control is that the level in thereservoir can be controlled to any level. The level can also be changedat any time and there will be a smooth transition between the old andnew levels. Use of the venous line clamp continuous level control systemalso increases patient safety because it will prevent emptying of thevenous reservoir 106 in case of temporary user inattention.

15. Venous Reservoir Level Control by Venous Reservoir Vacuum

The venous reservoir level control by venous reservoir vacuum procedure,initiated and/or enabled by contacting a graphic button (not shown) onuser interface 50 will result in the automatic control of venousreservoir vacuum to maintain the desired level or volume in the venousreservoir. As will be appreciated, the level control procedure will becontrolled in accordance with predetermined protocols stored in memory,and will entail automated steps. The user would select the desiredvenous reservoir level to maintain by contacting graphic buttons (notshown) and/or adjusting knob 52 on user interface 50.

This control protocol maintains the level in the venous reservoir 106 ata pre-selected value by controlling the level of vacuum in the venousreservoir. Typically, vacuum level control would most likely be usedwhen vacuum is already in use for vacuum assisted venous drainageprocedures in order for vacuum to have an effect on increasing orlowering level. The continuous level control is an operational mode bywhich the level of the reservoir is not allowed to decrease below orincrease above some pre-selected value that can be adjusted by the user.Use of this mode requires that a continuous level sensor such as thatdescribed with respect to FIG. 12 is present on the system to providefeedback of the current level of fluid in the reservoir. As the levelincreases above or decreases below the pre-selected value, a softwareand/or hardware implemented PID (Proportional, Integral, Differential)servo increases or decreases the vacuum in the venous reservoir tomaintain the preselected reservoir level resulting in the flow rate intothe reservoir closely matching the flow out of the reservoir. If vacuumis not currently in use in the venous reservoir, the ability to reducevacuum to lower the reservoir level would not exist. In this case vacuumreservoir level control would only be one sided whereby vacuum couldonly be added and used to increase the level in the reservoir level.

The advantage of this method of level control is that the level in thereservoir can be controlled to any level. The level can also be changedat any time and there will be a smooth transition between the old andnew levels. Use of the venous reservoir vacuum continuous level controlsystem also increases patient safety because it will prevent emptying ofthe venous reservoir 106 in case of temporary user inattention.

16. Automatic Fluid Shuttling

The automatic fluid shuttling procedure, initiated and/or enabled bycontacting a graphic button (not shown) on user interface 50 will resultin the automatic control of venous line clamp 46 to transfer apreselected volume of fluid to or from the bypass circuit to the patientduring bypass. As will be appreciated, the automatic fluid shuttlingprocedure will be controlled in accordance with predetermined protocolsstored in memory, and will entail automated steps. The user would selectthe desired volume to transfer by contacting graphic buttons (not shown)and/or adjusting knob 52 on user interface 50.

To transfer fluid to the patient, the system control automaticallysenses the current level in the venous reservoir 106 and causes thevenous line clamp 46 to reduce flow by restricting the venous lineand/or the arterial pump to increase flow by increasing the pump speeduntil the selected volume has been transferred to the patient. Eitherthe venous line clamp 46 setting or the arterial pump 31 flow settingmode is selectable by the user by contacting graphic buttons (not shown)and/or adjusting knob 52 on user interface 50. At completion of thevolume transfer the venous line clamp and/or the arterial pump willreturn to their previous settings. To transfer fluid from the patient,the system control automatically senses the current level in the venousreservoir and causes the venous line clamp 46 to increase flow and/orthe arterial pump 31 to decrease flow until the selected volume has beentransferred from the patient. The venous line clamp 46 setting or thearterial pump 31 flow setting, which ever mode was used, will return tothe previous settings after completing the volume transfer.

17. Variable Minimum Reservoir Level

The variable minimum reservoir level control procedure, initiated and/orenabled by contacting a graphic button (not shown) on user interface 50will result in the automatic control of arterial pump 31 to a safe flowrate to prevent emptying the venous reservoir and ensure that air is notintroduced into the venous reservoir outlet line. As will beappreciated, the variable minimum reservoir level procedure will becontrolled in accordance with predetermined protocols stored in memory,and will entail automated steps.

To ensure the venous reservoir 106 is not emptied when operating atlower levels in the venous reservoir and to ensure that air is notintroduced into the venous reservoir outlet line 110 due to high flowrates causing air generation from vortexing or entrained air to enterthe venous reservoir outlet, the arterial pump 31 flow is automaticallyreduced as the venous reservoir level decreases. Typically, theautomatic slow down of arterial pump 31 occurs at levels below 200 ml to500 ml. For example, as the venous reservoir level decreases below 200ml, the arterial pump would begin to reduce flow to a safe flow rate. Asthe level in the reservoir continues to decrease, the arterial pump flowwould also continue to decrease flow until the safe flow rate for thatlevel in the reservoir is reached. The safe flow rate for the arterialpump 31 at a given venous reservoir level is based on determining thecurrent volume in venous reservoir 106, and determining the time itwould take to safely stop the arterial pump (i.e., how fast the arterialpump 31 can be stopped without emptying the venous reservoir) anddetermining the maximum operable flow rate where air would be preventedfrom entering the venous reservoir outlet tubing 110 due to vortexing orair entrainment. From the venous reservoir level, the time required tosafely stop the arterial pump, and the maximum operable flow rate for agiven level, the safe arterial pump flow rate for a given venousreservoir level can be determined.

The advantage of using this low level slow down technique is that thearterial pump flow rate is reduced depending upon the reservoir leveland there are no abrupt stops and starts of the arterial pump. Thissmoother control helps improve safety with less chance of entraining airinto the venous reservoir outlet tubing 110.

Existing systems that do not have an available continuous level sensorcannot provide an equivalent form of pump slow down at low reservoirlevels. A discreet single level sensor, used on some perfusion systems,can only provide a pump shut down at that level, with the possibility ofreverting to some sort of oscillation of the pump around that level.

Alternatively, a system using two discreet level sensors could be usedto provide a form of level control to maintain level between thelocations of these two sensors. The control point is then fixed and noadvanced slow down of the pump is possible using this configuration asdescribed above but the arterial pump flow could be increased or reducedto keep the venous reservoir level essentially between the two discretelevel sensors.

18. Auto Arterial Line Clamp with Arterial Pump Stop

The automatic arterial line clamp with arterial pump stop procedure,initiated and/or enabled by contacting a graphic button (not shown) onuser interface 50 will result in the automatic open or close arterialline clamp 92 if arterial pump 31 is started or stopped. As will beappreciated, the automatic line clamp procedure will be controlled inaccordance with predetermined protocols stored in memory, and willentail automated steps.

This protocol may automatically close the arterial line clamp 92 inarterial line 122 when arterial pump 31 is stopped. This preventsdraining the patient through the under occluded pump or possibly drawingair through the cannula purse strings if arterial pump 31 is stopped.Conversely, arterial line clamp 92 in arterial line 122 may open whenarterial pump 31 is started.

19. Auto Venous Line Clamp with Arterial Pump Stop

The automatic venous line clamp with arterial pump stop procedure,initiated and/or enabled by contacting a graphic button (not shown) onuser interface 50 will result in the automatic open or close of venousline clamp 46 if arterial pump 31 is started or stopped. As will beappreciated, the automatic venous line clamp procedure will becontrolled in accordance with predetermined protocols stored in memory,and will entail automated steps.

This protocol may automatically close venous line clamp 46 in venousline 104 when arterial pump 31 is stopped. This prevents exsanguinationof the patient or overflowing the venous reservoir 106 if arterial pump31 was stopped and venous line clamp 46 was left open. Conversely,venous line clamp 46 in venous line 104 may open when arterial pump 31is started.

20. Automatic Cardioplegia Delivery

The automatic cardioplegia delivery procedures herein described below,initiated and/or enabled by contacting graphic buttons (not shown) onuser interface 50 will result in the automatic control of cardioplegiacircuit pumps and valves to facilitate delivery of cardioplegia deliverysolutions. As will be appreciated, the automatic cardioplegia deliveryprocedures will be controlled in accordance with predetermined protocolsstored in memory, and will entail automated steps. The user would selectthe cardioplegia delivery parameters by contacting graphic buttons (notshown) and/or adjusting knob 52 on user interface 50.

In one automatic cardioplegia delivery procedure, the cardioplegiapatient valve 96 and pre-selected crystalloid solution valve 99 can beautomatically opened when delivery begins (i.e., when cardioplegia pumps35 and or 36 are operated) and both the cardioplegia patient valve 96and the pre-selected crystalloid solution valve 99 can be automaticallyclosed when delivery stops (i.e., when cardioplegia pumps 35 and 36 arestopped).

In another cardioplegia automated feature, the user can pre-selectdifferent ratios for each of the cardioplegia crystalloid bags 136.During cardioplegia delivery, control unit 10 will automatically invokethe pre-selected ratio for the respective crystalloid bag 136 selectedfor delivery to the patient.

Additionally, cardioplegia may be automatically delivered to the patientby either volume delivery (i.e., where a pre-selected bolus volume isdelivered to the patient and when the pre-selected volume is delivered,cardioplegia delivery is terminated) or time delivery (i.e., where acardioplegia bolus is delivered for a pre-selected amount of time and atthe end of the pre-selected time, cardioplegia delivery is terminated)or cardioplegia may be delivered manually where the user manually startscardioplegia until a volume or time has expired and whereby the usermanually terminates cardioplegia delivery.

Additionally, cardioplegia crystalloid valves 99 can be alternatelyopened and closed while operating crystalloid pump 36 to allow variableconcentration, fixed dilution delivery. The first crystalloid valve 99is opened to draw in a specific volume of crystalloid solutioncontaining a first set of constituent ingredients. Then the second valve99 is opened to draw in a second specific volume of crystalloid solutionsecond set of constituent ingredients. Typically, the two crystalloidsolutions contain one or more different constituent ingredients wherebythe mixing of the two crystalloid solutions at the pre selectedproportions will yield the desired concentrations for cardioplegiadelivery. The proportion of the volumes drawn from each crystalloid bag136 determines the resultant crystalloid constituent concentration(s).

21. Vacuum Assisted Venous Drainage (VAVD) Feedback/Control

During vacuum assisted venous drainage the vacuum is used to augment thevenous return from the patient to ensure there is adequate flow from thepatient to maintain the patient on bypass. When flow rates are reducedduring the procedure while moving or filling the heart, at the end ofthe procedure, or any other reason, the vacuum may not be necessary tomaintain flow and may create unsafe vacuum levels on circuit componentswhich may cause air to enter the patient circuits.

The automatic vacuum assisted venous drainage (VAVD) feedback/controlprocedure, initiated and/or enabled by contacting a graphic button (notshown) on user interface 50 will result in the automatic control of thevenous reservoir vacuum pump or pressure regulator to prevent adverseeffects of vacuum on various circuit components. As will be appreciated,the automatic vacuum assisted venous drainage (VAVD) feedback/controlprocedure will be controlled in accordance with predetermined protocolsstored in memory, and will entail automated steps.

To prevent the possibility of negative effects from the vacuum, such ascreating a negative pressure acting on the oxygenator membrane anddrawing air across membrane into the blood lines, the vacuum can bereduced or stopped through control of a vacuum regulator (not shown) orvacuum pump (not shown) as the arterial pump 31 flow is reduced. Oncethe system detects the arterial pump 31 is slowing down, the vacuum canbe reduced to maintain the level in the reservoir. This control methodis similar to venous reservoir level control with vacuum as previouslydescribed herein.

Additionally, if arterial pump 31 is stopped the venous reservoir vacuumcan be turned off to ensure negative pressure is not applied to theoxygenator or other circuit elements that may not operate properly undernegative pressure. In addition to turning the vacuum off control unit 10can also vent the venous reservoir to atmosphere to quickly relieve thevacuum in the venous reservoir through the operation of a vacuumregulator or valve (not shown).

Additionally, if positive pressure is created in the venous reservoirfor example due to a malfunction of a passive pressure relief valve, thepositive pressure can be automatically released by the vacuum regulatoror valve (not shown) to prevent pressure build up inside the venousreservoir as the pressure exceeds a predetermined value.

22. Automatic Hemoconcentration

The automatic hemconcentration procedures herein described below,initiated and/or enabled by contacting graphic buttons (not shown) onuser interface 50 will result in the automatic control ofhemoconcentrator pumps and valves to facilitate hemoconcentration. Aswill be appreciated, the automatic hemoconcentration delivery procedureswill be controlled in accordance with predetermined protocols stored inmemory, and will entail automated steps.

The user would select the hemoconcentration parameters by contactinggraphic buttons (not shown) and/or adjusting knob 52 on user interface50.

A two pump hemoconcentration system as described previously with respectto FIG. 3B uses a blood inflow pump 37 to the hemoconcentrator and ablood outflow pump 38 from the hemoconcentrator. It has a pressuremonitor 86 on the hemoconcentrator blood inlet. The pressure sensormonitors the inlet pressure to ensure the pressure does not exceed apredetermined value where an alarm would occur on user interface 50and/or both the inflow and outflow pumps could be slowed or stopped.There is also a valve 39 on the waste line which is closed during aportion of the priming sequence to prevent the prime solution from beingpassed through the hemoconcentrator and later opened to allow primingacross the hemoconcentrator membrane or the valve could be used toprovide a restriction on the hemoconcentrator effluent line to reduceeffluent flow. Effluent rate and volume could be precisely controlledand determined by controlling the inflow and outflow pump flow rates.The inflow pump flow rate would be greater than the outflow pump flowrate to ensure air is not drawn into the hemoconcentrator circuit acrossthe hemoconcentrator membrane. The effluent rate or ultrafiltrate rateequals the difference between inflow and outflow blood pump rates. Thecontrol unit 10 could automatically operate both pumps at respectiveflow rates to deliver a user selected effluent rate or a user selectedeffluent volume in a user selected period of time. A scale could beadded on the ultrafiltrate waste bag to weigh the effluent to determinethe effluent volume.

Alternatively, the outflow pump could be replaced with a variablerestrictor valve (not shown) on the blood out flow line from thehemoconcentrator to change the transmembrane pressure (TMP) which is thedriving force of the effluent across the hemoconcentrator membrane.Restricting the valve would increase TMP, subsequently increasingeffluent rate and opening the valve would decrease TMP, subsequentlydecreasing effluent rate.

Additionally, a hematocrit sensor (not shown) could be added in thecircuit to measure the hematocrit at the outlet of the hemoconcentrator.The control unit 10 could use the outlet hematocrit information and theinlet hematocrit information as measured at hematocrit sensor 85 or onlythe hemoconcentrator outlet hematocrit to feedback to and automaticallyadjust the hemoconcentrator inlet and outlet flow rate to yield a userselected hematocrit of the blood exiting the hemoconcentrator.

23. Correct Pump Load and Circuit Test

This is a series of automatic tests performed by control unit 10 inconjunction with disposable assembly 100 to determine if the pumpheaders are loaded properly, if the suction, vent and cardioplegia pumpsare fully occluded, and if the arterial pump is overoccluded orunderoccluded.

The automatic pump load and circuit test procedures herein describedbelow, may be automatically initiated during or after disposable loadand/or priming will result in the automatic operation of any pump orvalve to test the disposable assembly for proper loading and orfunction. As will be appreciated, the automatic pump load and circuittest procedures will be controlled in accordance with predeterminedprotocols stored in memory, and will entail automated steps. The userwould select the user settable pump load and circuit test parameters bycontacting graphic buttons (not shown) and/or adjusting knob 52 on userinterface 50.

After loading disposable assembly 100 on control unit 10 the suction andvent pumps can be automatically operated to test for correct loading orfor leaks in their respective circuits. The patient lines 170, 172 and186 of these circuits are sealed by connection to plugs or some otherconnector or connectors that seal the ends of lines 170, 172, and 186.The sealing may occur during assembly of disposable assembly 100 or thelines could be clamped by the user during the test. The test isperformed by operating the two suction pumps and vent pump at apredetermined or user selected speed or flow rate over a predeterminedor user selected time period. As the pumps are operated a vacuum isgenerated in the suction and vent circuits and measured at pressuresensors 40, 42, and 44 until a predetermined pressure is reached wherethe respective pumps are stopped. If a positive pressure is generatedthis indicates the pump tubing lines 178, 180, and 190 are probablyloaded incorrectly (i.e., reversed) and an alarm occurs advising theuser of the condition and any appropriate checks or corrective actionsthat should occur. If the predetermined pressure cannot be reachedduring the predetermined test time period this indicates a leak existsin the circuit and an alarm occurs advising the user of the test failurewhich may include advisory messages in checking for the leak orresolution of the problem. If the predetermined pressure is reached thepumps are stopped and a pressure decay test is performed which monitorsthe pressure at sensors 40, 42, and 44 and if a predetermined pressureloss over a predetermined time occurs a leak may exist in the circuitand an alarm occurs advising the user of the test failure and anyappropriate checks or corrective actions that should occur. If thepressure at sensors 40, 42, and 44 reach the predetermined pressurelimit and no significant pressure decay occurs, the circuit is notleaking, the pump tubing has been loaded correctly and the pump is fullyocclusive on the pump tubing.

A similar test is performed on the cardioplegia circuit. For thecardioplegia circuit the cardioplegia patient valve 96 is closed and thepumps (35, 36) are operated at a predetermined flow one pump at a timewhich creates a positive pressure in the circuit to a predeterminedpressure as measured at pressure sensor 18. If the predeterminedpressure cannot be reached during the predetermined test time periodthis indicates a leak exists in the circuit and an alarm occurs advisingthe user of the test failure which may include advisory messages inchecking for the leak or resolution of the problem. If the predeterminedpressure is reached the pumps are stopped and a pressure decay test isperformed which monitors the pressure at sensor 18 and if apredetermined pressure loss over a predetermined time occurs a leak mayexist in the circuit and an alarm occurs advising the user of the testfailure and any appropriate checks or corrective actions that shouldoccur. If the pressure at 18 reaches the predetermined pressure limitand no significant pressure decay occurs, the circuit is not leaking,the pump tubing has been loaded correctly and the pump is fullyocclusive on the pump tubing. This test is repeated for the secondcardioplegia pump. The test is performed one cardioplegia pump at a timebecause the two pumps share the same outlet connection which if the twopumps are operated simultaneously they may mask a small leak.

The arterial-venous circuit (A-V circuit) could be checked in a similarmanner as herein described once the arterial circuit has been primed.The circuit requires priming because air alone would not hold pressuresince the pressure would leak across the oxygenator membrane. The testwould be conducted in a similar manner as described herein with similaralarm messages.

Alternatively, a pressure sensor (not shown) could be added to the A-Vcircuit on the outlet of the arterial pump 31 between the arterial pumpand the oxygenator 112 and a valve (not shown) could be added andpositioned downstream of the pressure sensor just described. Using thispressure sensor and valve, a similar circuit pressure test as previouslydescribed herein for the cardioplegia pumps could be performed to checkfor circuit leaks, correct loading of the tubing line and pump occlusionin the A-V circuit.

After auto prime, the system may be checked for leaks by closing variousvalves, and operating various pumps in various combinations andmonitoring respective pressures and pressure decay rates and providingalarms advising the user of circuit or equipment problems if thepredetermined pressure limits are not reached or the pressure decayrates exceeded.

Additionally, by pressurizing the priming solution in the oxygenator toa predetermined value, leaks in the membrane can be detected with theliquid leak detector 366 shown on FIG. 26 as fluid would transverse aleaky oxygenator membrane at a predetermined pressure.

24. Arterial Pump Occlusion Setting Assist

The automatic pump occlusion setting assist procedures herein describedbelow, initiated and/or enabled by contacting the graphic “checkocclusion” button on user interface 50 will result in the automaticcontrol of arterial pump 31 and valves 92, 405 and 406 while monitoringpressure at pressure sensor 14 to aid in setting the arterial pumpocclusion. As will be appreciated, the automatic pump occlusion settingassist procedures will be controlled in accordance with predeterminedprotocols stored in memory, and will entail automated steps. The userwould select the user settable parameters by contacting graphic buttons(not shown) and/or adjusting knob 52 on user interface 50. The occlusioncheck normally occurs after priming but could occur after loadingdisposable assembly 100 and before prime.

After initiation of the automatic pump occlusion setting assist,arterial patient line valve 92, and purge valves 405, 406 are closed andarterial pump 31 is operated at a predetermined speed for a predeterminetime. If the arterial pump outlet pressure as measured at pressuresensor 14 exceeds a predetermined pressure value, the pump is stoppedand purge valves 405 and/or 406 are opened to release the pressure andthe occlusion is determined to be over occluded. The user is advisedthrough user interface 50 of the overoccluded condition and the user isinstructed to reduce the occlusion by a predetermined amount and torepeat the test by contacting the check occlusion button (#) on userinterface 50. If the predetermined pressure value is not reached, theaverage pressure is calculated. If the average pressure is greater thana second predetermined pressure value, the user is instructed to reducethe occlusion by a predetermined amount and to repeat the test bycontacting the check occlusion button on user interface 50. If theaverage pressure is less than a third predetermined pressure value, theuser is instructed to increase the occlusion by a predetermined amount.If the average pressure is between the second and third pressure values,the occlusion setting is determined to be acceptable and the user isadvised of that on user interface 50. The occlusion test is repeateduntil the pressure is in the predetermined acceptable range or the userends the test.

A polynomial is used to determine the occlusion adjustment amount forboth reducing or increasing occlusion for an over pressure condition orunder pressure condition respectively.

Alternatively, a method of measuring occlusion is to close the arterialline valve 92 and the purge valves 405 and 406, then operate arterialpump 31 until a predetermined pressure has been reached. The arterialpump is then stopped and the pressure decay (i.e., pressure drop over aperiod of time) is determined by recording the measured pressure atpressure sensor 14 at predetermined time intervals. A decay rate of apredetermined range of values would result in an acceptable occlusion. Adecay rate exceeding the predetermined decay rate range of values wouldindicate an underocclusion setting and the user would be instructed toincrease occlusion as described herein above. A decay rate less than thepredetermined decay rate range of values would indicate an overocclusion setting and the user would be instructed to decrease occlusionas described herein above.

25. Arterial Pump Occlusion Setting Methods Using the Cardioplegia BloodPump.

The automatic pump occlusion setting assist procedures herein describedbelow, initiated and/or enabled by contacting a graphic “checkocclusion” button on user interface 50 will result in the automaticcontrol of cardioplegia blood pump 34 and valves 92, 405 and 406 whilemonitoring pressure at pressure sensor 14 to aid in setting the arterialpump occlusion. As will be appreciated, the automatic pump occlusionsetting assist procedures will be controlled in accordance withpredetermined protocols stored in memory, and will entail automatedsteps. The user would select the user setable parameters by contactinggraphic buttons (not shown) and/or adjusting knob 52 on user interface50. The occlusion check normally occurs after priming but could occurafter loading disposable assembly 100 and before prime.

The cardioplegia blood pump 34 can be operated in reverse, pumping fluidbackwards through the under-occluded arterial pump, while monitoring thearterial line pressure as measured at pressure sensor 14 and witharterial patient valve 92, purge valves 405 and 406 all closed. The flowrate and pressure generated would indicate the occlusion as in a similarmanner as previously described herein.

Alternatively, the cardioplegia blood pump can be operated in theforward direction, with the arterial pump pumping at a predetermined RPMand the arterial outlet line clamped. The speed of the cardioplegiablood pump can be varied to maintain a constant pressure in the arterialline as measured at pressure sensor 14. The difference between thepredicted arterial pump flow at full occlusion and the cardioplegia pumpflow rate would be the leakage rate due to under-occlusion. (A positivepressure must be maintained to prevent air passing across the oxygenatormembrane.)

The description provided above is strictly for exemplary purposes.Numerous modifications, extensions and adaptations of the presentinvention will be apparent to those skilled in the art uponconsideration, and are intended to be within the scope of the presentinvention.

1. In an extracorporeal blood perfusion system for receiving blood froma patient through a venous line, oxygenating the blood, and returningthe oxygenated blood to the patient through an arterial line, a methodof preventing the return of oxygenated blood containing gaseous bubblesto the patient, the extracorporeal blood perfusion system including acardiopulmonary blood circuit having a plurality of tubing linesinterconnecting a venous reservoir, a blood oxygenator and an arterialblood filter, the method comprising: connecting the blood perfusionsystem for receiving venous blood from the patient and returningoxygenated blood to the patient; providing an air purge line including apurge valve having an open position for opening the purge line and aclosed position for closing the purge line; fluidly connecting a firstend of the purge line with an outlet of the oxygenator and a second endof the purge line with an inlet of the venous reservoir; and providing acontrol unit having a sensor for determining the presence of gaseousbubbles in a tubing line connected to an outlet of the oxygenator, thecontrol unit being connected to the first pump for controlling the speedof the first pump and being connected to the purge valve forautomatically opening the purge valve when gaseous bubbles are sensed bythe sensor such that at least a portion of the oxygenated blood isdiverted from the patient through the air purge line back to the venousreservoir.
 2. The method of claim 1 wherein the step of fluidlyconnecting the first and second ends of the purge line includesconnecting the first end of the purge line to a purge port on thearterial blood filter.
 3. The method of claim 1 further includingproviding an arterial valve in the arterial line, the arterial valvehaving an open position for opening the arterial line and a closedposition for closing the arterial line and wherein the step of providinga control unit includes providing a control unit connected to thearterial valve for automatically closing the arterial valve when gaseousbubbles are sensed by the sensor.
 4. The method of claim 1 wherein thestep of providing a control unit includes providing a control unitconnected to the first pump for automatically slowing the speed of thefirst pump when gaseous bubbles are sensed by the sensor.